Areas Related to Circles: 1 mark Questions (CBSE Class 10)
63 different 1 mark questions on Areas Related to Circles from CBSE Class 10 Maths board exams 2022–2026, newest first.
Chord AB subtends an angle of 4 0 ∘ at the centre of the circle of radius 9 cm. The length of arc AB is :
(A) 7 22 cm(B) 7 198 cm(C) 7 44 cm(D) 7 54 cm
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Answer: (C) 7 44 cm
Arc length = 36 0 ∘ θ × 2 π r . = 360 40 × 2 × 7 22 × 9 = 7 44 cm.
An arc of length 11 cm subtends an angle of 10 5 ∘ at the centre of the circle. The radius of the circle is :
(A) 8 cm(B) 4 3 cm(C) 6 cm(D) 7 cm
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Answer: (C) 6 cm
Arc length = 36 0 ∘ θ × 2 π r . 11 = 360 105 × 2 × 7 22 × r = 6 11 r .r = 6 cm.
The length of a pendulum is 70 cm and it describes an arc of length 88 cm when swings. The angle subtended by the arc at the centre is
(A) 3 6 ∘ (B) 7 0 ∘ (C) 7 2 ∘ (D) 8 0 ∘
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Answer: (C) 7 2 ∘
Arc length = 36 0 ∘ θ × 2 π r 88 = 36 0 ∘ θ × 2 × 7 22 × 70 = 36 0 ∘ θ × 440 θ = 440 88 × 36 0 ∘ = 7 2 ∘
The length of the arc of the sector of a circle with radius 21 cm and of central angle 6 0 ∘ , is :
(A) 22 cm(B) 44 cm(C) 88 cm(D) 11 cm
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Answer: (A) 22 cm
Arc length = 36 0 ∘ θ × 2 π r = 360 60 × 2 × 7 22 × 21 . = 6 1 × 132 = 22 cm.
The hour hand of a clock is 7 cm long. The angle swept by it between 7:00 a.m. and 8:10 a.m. is :
(A) ( 4 35 ) ∘ (B) ( 2 35 ) ∘ (C) 3 5 ∘ (D) 7 0 ∘
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Answer: (C) 3 5 ∘
The hour hand turns 3 0 ∘ in 60 minutes, i.e. 2 1 ∘ per minute. From 7:00 a.m. to 8:10 a.m. is 70 minutes. Angle swept = 70 × 2 1 = 3 5 ∘ .
Shown in the given figure is a circle with centre O. The area of the minor sector is 7 cm2 . Area of circle is :
(A) 84 π cm2 (B) 11 84 cm2 (C) 84 cm2 (D) π 84 cm2
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Answer: (C) 84 cm2
The minor sector has angle 3 0 ∘ , which is 360 30 = 12 1 of the circle. Area of circle = 12 × 7 = 84 cm2 .
In the given figure, O is the centre of circle. XYZ is an arc of the circle subtending an angle of 4 5 ∘ at the centre. If the radius of the circle is 32 cm, then the length of the arc XYZ is :
(A) 4 π cm(B) 8 π cm(C) 64 π cm(D) 128 π cm
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Answer: (B) 8 π cm
Arc length = 36 0 ∘ θ × 2 π r = 360 45 × 2 π × 32 . = 8 1 × 64 π = 8 π cm.
Area of a segment of a circle of radius 'r' and central angle 6 0 ∘ is :
(A) 2 π r 2 − 2 1 r 2 (B) 4 2 π r − 4 3 r 2 (C) 6 π r 2 − 4 3 r 2 (D) 4 2 π r − r 2 sin 6 0 ∘
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Area of sector = 360 60 π r 2 = 6 π r 2 . The triangle formed by the two radii is equilateral, area = 4 3 r 2 . Area of segment = 6 π r 2 − 4 3 r 2 .
The area of a semicircle of diameter 'd' is :
(A) 16 π d 2 (B) 4 π d 2 (C) 8 π d 2 (D) 2 π d 2
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Answer: (C) 8 π d 2
Radius = 2 d . Area of semicircle = 2 1 π ( 2 d ) 2 = 8 π d 2
A circle is divided into 16 identical sectors. If radius of the circle is 7 cm, area of each sector is
(A) 4 77 cm2 (B) 77 cm2 (C) 154 cm2 (D) 8 77 cm2
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Answer: (D) 8 77 cm2
Area of circle = 7 22 × 7 × 7 = 154 cm2 Area of each sector = 16 154 = 8 77 cm2
Arc PQ subtends an angle θ at the centre of the circle with radius 6.3 cm. If P Q ⌢ = 11 cm, then the value of θ is
(A) 1 0 ∘ (B) 6 0 ∘ (C) 4 5 ∘ (D) 10 0 ∘
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Answer: (D) 10 0 ∘
Arc length = 36 0 ∘ θ × 2 π r 11 = 36 0 ∘ θ × 2 × 7 22 × 6.3 = 36 0 ∘ θ × 39.6 θ = 39.6 11 × 36 0 ∘ = 10 0 ∘
Area of sector of a circle with radius 18 cm is 198 cm2 . The measure of central angle is
(A) 7 0 ∘ (B) 1 4 ∘ (C) 14 0 ∘ (D) 21 0 ∘
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Answer: (A) 7 0 ∘
36 0 ∘ θ × 7 22 × 18 × 18 = 198 θ = 22 × 324 198 × 36 0 ∘ × 7 = 7 0 ∘
An arc of length 2.2 cm subtends an angle θ at the centre of the circle with radius 2.8 cm. The value of θ is
(A) 5 0 ∘ (B) 6 0 ∘ (C) 4 5 ∘ (D) 3 0 ∘
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Answer: (C) 4 5 ∘
Arc length = 36 0 ∘ θ × 2 π r 2.2 = 36 0 ∘ θ × 2 × 7 22 × 2.8 = 36 0 ∘ θ × 17.6 θ = 17.6 2.2 × 36 0 ∘ = 4 5 ∘
The area of a sector of a circle of radius 10 cm is 3 55 c m 2 . The value of central angle is
(A) 2 2 1 ∘ (B) 4 2 ∘ (C) 10 5 ∘ (D) 2 1 ∘
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Answer: (D) 2 1 ∘
36 0 ∘ θ × 7 22 × 1 0 2 = 3 55 θ = 3 55 × 2200 7 × 36 0 ∘ = 2 1 ∘
The perimeter of the shaded region in the given figure is :
(A) l (B) l + a (C) l + 2 r (D) l + 2 r + a
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Answer: (C) l + 2 r
The shaded region is the sector bounded by the two radii and the arc. Its perimeter = r + r + l = l + 2 r .
The ratio of the area of a quadrant of a circle to the area of the same circle is :
(A) 1 : 2(B) 2 : 1(C) 1 : 4(D) 4 : 1
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Answer: (C) 1 : 4
Area of quadrant = 4 1 π r 2 , so the ratio is 4 1 π r 2 : π r 2 = 1 : 4 .
In the given figure, the shaded region represents :
(A) minor sector(B) major sector(C) minor segment(D) major segment
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Answer: (C) minor segment
The shaded region is bounded by a chord and the smaller arc cut off by it. The region between a chord and the minor arc is the minor segment.
The perimeter of a quadrant of a circle of radius r is :
(A) 4 1 π r 2 (B) 4 1 π r 2 + 2 r (C) 2 π r (D) 2 π r + 2 r
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Answer: (D) 2 π r + 2 r
A quadrant is bounded by an arc of 4 1 of the circumference and two radii. Arc = 4 1 × 2 π r = 2 π r . Perimeter = 2 π r + 2 r .
The area of a quadrant of a circle of radius ‘2r’ is :
(A) 4 1 π r 2 (B) 2 1 π r 2 (C) π r 2 (D) 2 π r 2
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Answer: (C) π r 2
Area of quadrant = 4 1 π ( 2 r ) 2 = 4 1 × 4 π r 2 = π r 2 .
The ratio of the area of a quadrant of a circle to the area of a circle is :
(A) 2 : 1(B) 1 : 2(C) 1 : 4(D) 4 : 1
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Answer: (C) 1 : 4
Area of quadrant = 4 1 π r 2 . Ratio = 4 1 π r 2 : π r 2 = 1 : 4 .
The angle of the sector of a circle whose area is one-eighth of the area of the circle is :
(A) 22 2 1 ∘ (B) 4 5 ∘ (C) 6 0 ∘ (D) 9 0 ∘
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Answer: (B) 4 5 ∘
36 0 ∘ θ × π r 2 = 8 1 π r 2 .θ = 8 36 0 ∘ = 4 5 ∘ .
The perimeter of a quadrant of a circle of circumference 22 cm is :
(A) 29 cm(B) 22 cm(C) 12.5 cm(D) 5.5 cm
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Answer: (C) 12.5 cm
2 π r = 22 ⇒ r = 2 × 22 22 × 7 = 3.5 cm.Perimeter of quadrant = 4 22 + 2 r = 5.5 + 7 = 12.5 cm.
The length of arc subtending an angle of 21 0 ∘ at the centre of the circle, is 3 44 cm. The radius of the circle is :
(A) 2 2 cm(B) 4 cm(C) 8 cm(D) 4 1 cm
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Answer: (B) 4 cm
Arc length = 36 0 ∘ θ × 2 π r . 360 210 × 2 × 7 22 × r = 3 44 3 11 r = 3 44 , so r = 4 cm.
The perimeter of a quadrant of a circle of radius 7 cm, is :
(A) 18 cm(B) 11 cm(C) 22 cm(D) 25 cm
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Answer: (D) 25 cm
Perimeter = 2 r + 4 1 × 2 π r . = 14 + 4 1 × 2 × 7 22 × 7 = 14 + 11 = 25 cm.
An arc of length 22 cm subtends an angle of x ∘ at the centre of the circle. If radius of circle is 36 cm, the value of x is
(A) 35(B) 40(C) 60(D) 30
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Answer: (A) 35
Arc length = 360 x × 2 π r . 22 = 360 x × 2 × 7 22 × 36 = 70 44 x .x = 44 22 × 70 = 35 .
An arc of length 'l ' subtends an angle of 1 5 ∘ at the centre of a circle of radius 8.4 cm. The value of l is
(A) 22 cm(B) 2.2 cm(C) 9.24 cm(D) 4.2 cm
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Answer: (B) 2.2 cm
l = 36 0 ∘ θ × 2 π r = 360 15 × 2 × 7 22 × 8.4 .= 24 1 × 52.8 = 2.2 cm.
OAB is sector of a circle with centre O and radius 7 cm. If length of arc A B ⌢ = 3 22 cm, then ∠ A O B is equal to
(A) ( 7 120 ) ∘ (B) 4 5 ∘ (C) 6 0 ∘ (D) 3 0 ∘
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Answer: (C) 6 0 ∘
Arc length = 36 0 ∘ θ × 2 π r . 3 22 = 36 0 ∘ θ × 2 × 7 22 × 7 = 36 0 ∘ θ × 44 .θ = 3 22 × 44 36 0 ∘ = 6 0 ∘ .
If a sector of a circle has an area of 40 π sq. units and a central angle of 7 2 ∘ , the radius of the circle is :
(A) 200 units(B) 100 units(C) 20 units(D) 10 2 units
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Area of sector = 360 72 × π r 2 = 5 π r 2 . 5 π r 2 = 40 π , so r 2 = 200 .r = 200 = 10 2 units.
A piece of wire 20 cm long is bent into the form of an arc of a circle of radius π 60 cm. The angle subtended by the arc at the centre of the circle is :
(A) 3 0 ∘ (B) 6 0 ∘ (C) 9 0 ∘ (D) 5 0 ∘
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Answer: (B) 6 0 ∘
Arc length = 36 0 ∘ θ × 2 π r . 20 = 36 0 ∘ θ × 2 π × π 60 = 36 0 ∘ θ × 120 .θ = 120 20 × 36 0 ∘ = 6 0 ∘ .
An arc of a circle is of length 5 π cm and the sector it bounds has an area of 20 π cm2 . Its radius is :
(A) 10 cm(B) 1 cm(C) 5 cm(D) 8 cm
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Answer: (D) 8 cm
Area of sector = 2 1 × arc length × r . 20 π = 2 1 × 5 π × r r = 5 π 40 π = 8 cm.
If a large circular pizza is divided into 5 equal sectors, then the central angle of each sector will be :
(A) 6 0 ∘ (B) 9 0 ∘ (C) 4 5 ∘ (D) 7 2 ∘
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Answer: (D) 7 2 ∘
Central angle = 5 36 0 ∘ = 7 2 ∘
If an arc of a circle of diameter 10 cm subtends an angle of 14 4 ∘ at the centre of the circle, then the length of the arc is :
(A) 2 π cm(B) 4 π cm(C) 5 π cm(D) 6 π cm
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Answer: (B) 4 π cm
Radius = 5 cm Arc length = 360 144 × 2 π × 5 = 5 2 × 10 π = 4 π cm
If the area of a sector of circle of radius 36 cm is 54 π cm2 , then the length of the corresponding arc of the sector is :
(A) 8 π cm(B) 6 π cm(C) 4 π cm(D) 3 π cm
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Answer: (D) 3 π cm
Area of sector = 2 1 × l × r . 54 π = 2 1 × l × 36 , so l = 3 π cm.
The diameter of a wheel is 63 cm. The distance travelled by the wheel in 100 revolutions is :
(A) 99 m(B) 198 m(C) 63 m(D) 136 m
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Answer: (B) 198 m
Distance in one revolution = circumference = π d = 7 22 × 63 = 198 cm. Distance in 100 revolutions = 198 × 100 = 19800 cm = 198 m.
The difference of the areas of a minor sector of angle 12 0 ∘ and its corresponding major sector of a circle of radius 21 cm, is
(A) 231 cm2 (B) 462 cm2 (C) 346.5 cm2 (D) 693 cm2
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Answer: (B) 462 cm2
Minor sector = 360 120 π r 2 = 3 1 π r 2 ; major sector = 3 2 π r 2 Difference = 3 1 π r 2 = 3 1 × 7 22 × 441 = 462 cm2
In the given figure, two concentric circles of radii 5 cm and 3 cm have their centre O. OAB is a sector of outer circle making an angle of 6 0 ∘ at the centre while OCD is the sector of smaller circle. The area of the shaded region is :
(A) 2 7 π cm2 (B) 3 8 π cm2 (C) 6 25 π cm2 (D) 2 3 π cm2
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Answer: (B) 3 8 π cm2
Shaded area = area of sector OAB − area of sector OCD. = 360 60 π ( 5 2 − 3 2 ) = 6 1 π × 16 = 3 8 π cm2 .
The region between a chord and either of the two arcs of a circle is called :
(A) an arc(B) a sector(C) a segment(D) a semicircle
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Answer: (C) a segment
By definition, the region bounded by a chord and either of its arcs is a segment of the circle.
In a circle of radius 21 cm, if an arc subtends an angle of 6 0 ∘ at the centre of the circle, then the length of the arc is :
(A) 11 cm(B) 44 cm(C) 7 22 cm(D) 22 cm
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Answer: (D) 22 cm
Arc length = 36 0 ∘ θ × 2 π r = 360 60 × 2 × 7 22 × 21 = 6 1 × 132 = 22 cm.
Area of a sector of angle θ (in degrees) of a circle with radius r is :
(A) 180 θ × 2 π r (B) 180 θ × π r 2 (C) 360 θ × 2 π r (D) 720 θ × 2 π r 2
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Answer: (D) 720 θ × 2 π r 2
Area of sector = 360 θ × π r 2 . 720 θ × 2 π r 2 = 360 θ × π r 2 , so option (D).
The area of the sector of a circle with radius 6 cm which subtends an angle of 6 0 ∘ at the centre of the circle is :
(A) 7 142 cm2 (B) 7 152 cm2 (C) 7 132 cm2 (D) 7 122 cm2
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Answer: (C) 7 132 cm2
Area = 360 60 × 7 22 × 6 × 6 = 6 1 × 7 792 = 7 132 cm2 .
If the area of a sector of a circle is 8 1 of the area of the circle, then the central angle of the sector is :
(A) 3 0 ∘ (B) 4 5 ∘ (C) 6 0 ∘ (D) 9 0 ∘
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Answer: (B) 4 5 ∘
Area of sector = 36 0 ∘ θ × π r 2 . 36 0 ∘ θ = 8 1 , so θ = 4 5 ∘ .
The length of an arc of a circle with radius 12 cm is 10 π cm. The central angle subtended by this arc at the centre, is :
(A) 12 0 ∘ (B) 6 ∘ (C) 7 5 ∘ (D) 15 0 ∘
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Answer: (D) 15 0 ∘
Arc length = 36 0 ∘ θ × 2 π r . 10 π = 36 0 ∘ θ × 24 π .θ = 24 10 × 36 0 ∘ = 15 0 ∘ .
The area of a quadrant of a circle whose circumference is 22 cm, is :
(A) 4 11 cm2 (B) 2 11 cm2 (C) 4 33 cm2 (D) 8 77 cm2
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Answer: (D) 8 77 cm2
2 π r = 22 , so r = 2 × 22 22 × 7 = 2 7 cm.Area of quadrant = 4 1 π r 2 = 4 1 × 7 22 × 4 49 = 8 77 cm2 .
The area of a sector of a circle of radius 16 cm cut off by an arc, which is 18.5 cm long, is :
(A) 168 cm2 (B) 148 cm2 (C) 154 cm2 (D) 176 cm2
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Answer: (B) 148 cm2
Area of sector = 36 0 ∘ θ π r 2 = 2 1 × ( 36 0 ∘ θ × 2 π r ) × r = 2 1 l r . Area = 2 1 × 18.5 × 16 = 148 cm2 .
Perimeter of a sector of a circle whose central angle is 9 0 ∘ and radius 7 cm is :
(A) 35 cm(B) 11 cm(C) 22 cm(D) 25 cm
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Answer: (D) 25 cm
Arc length = 360 90 × 2 × 7 22 × 7 = 11 cm. Perimeter = 2 r + arc = 14 + 11 = 25 cm.
If the area of a sector of a circle is 20 7 of the area of the circle, then the angle at the centre is equal to
(A) 11 0 ∘ (B) 13 0 ∘ (C) 10 0 ∘ (D) 12 6 ∘
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Answer: (D) 12 6 ∘
Area of sector = 36 0 ∘ θ × π r 2 = 20 7 π r 2 . θ = 20 7 × 36 0 ∘ = 12 6 ∘ .
If an arc subtends an angle of 9 0 ∘ at the centre of a circle, then the ratio of its length to the circumference of the circle is :
(A) 2 : 3(B) 1 : 4(C) 4 : 1(D) 1 : 3
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Answer: (B) 1 : 4
Arc length = 360 90 × 2 π r = 4 1 × 2 π r . Ratio of arc length to circumference = 4 1 = 1 : 4.
The area of the sector of a circle of radius 12 cm is 60 π cm2 . The central angle of this sector is :
(A) 12 0 ∘ (B) 6 ∘ (C) 7 5 ∘ (D) 15 0 ∘
Show answer & solution
Answer: (D) 15 0 ∘
Area of sector = 36 0 ∘ θ × π r 2 . 36 0 ∘ θ × 144 π = 60 π .θ = 144 60 × 36 0 ∘ = 15 0 ∘ .
Assertion (A) : If the circumference of a circle is 176 cm, then its radius is 28 cm. Reason (R): Circumference = 2 π × radius of a circle.
(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).(C) Assertion (A) is true, but Reason (R) is false.(D) Assertion (A) is false, but Reason (R) is true.
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Answer: (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Reason: circumference = 2 π r . True. Assertion: 2 × 7 22 × r = 176 gives r = 44 176 × 7 = 28 cm. True. The assertion follows directly from the formula in the reason, so R explains A.
If in the given figure, ∠ C = ∠ D = 9 0 ∘ , ∠ B = 6 0 ∘ and AP = 3 cm, then the area of the shaded region is :
(A) 3 π cm2 (B) 6 π cm2 (C) 7 π cm2 (D) 9 π cm2
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Answer: (A) 3 π cm2
∠ C + ∠ D = 18 0 ∘ , so CB ∥ DA.Then ∠ A + ∠ B = 18 0 ∘ , so ∠ D A B = 12 0 ∘ . The shaded region is a sector of radius AP = 3 cm and angle 12 0 ∘ . Area = 360 120 × π × 3 2 = 3 π cm2 .
The area of the square inscribed in a circle of radius 5 2 cm is :
(A) 50 cm2 (B) 100 cm2 (C) 25 cm2 (D) 200 cm2
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Answer: (B) 100 cm2
The diagonal of the inscribed square is a diameter = 10 2 cm. Side = 2 10 2 = 10 cm. Area = 1 0 2 = 100 cm2 .
The perimeter of the sector of a circle of radius 21 cm which subtends an angle of 6 0 ∘ at the centre of circle, is :
(A) 22 cm(B) 43 cm(C) 64 cm(D) 462 cm
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Answer: (C) 64 cm
Arc length = 360 60 × 2 × 7 22 × 21 = 22 cm. Perimeter = 22 + 21 + 21 = 64 cm.
The length of an arc of a circle with radius 12 cm is 10 π cm. The angle subtended by the arc at the centre of the circle, is :
(A) 12 0 ∘ (B) 6 ∘ (C) 7 5 ∘ (D) 15 0 ∘
Show answer & solution
Answer: (D) 15 0 ∘
36 0 ∘ θ × 2 π × 12 = 10 π .θ = 24 10 × 36 0 ∘ = 15 0 ∘ .
The area of a sector of angle α (in degrees) of a circle with radius R is :
(A) 180 α × 2 π R (B) 360 α × 2 π R (C) 180 α × π R 2 (D) 360 α × π R 2
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Answer: (d) 360 α × π R 2
Area of a sector = 36 0 ∘ angle × area of the circle = 360 α × π R 2
If the radius of a semi-circular protractor is 7cm, then its perimeter is :
(A) 11 cm(B) 14 cm(C) 22 cm(D) 36 cm
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Answer: (D) 36 cm
Perimeter of a semicircle = π r + 2 r . = 7 22 × 7 + 2 × 7 = 22 + 14 = 36 cm.
The length of the arc of a circle of radius 14 cm which subtends an angle of 6 0 ∘ at the centre of the circle is :
(A) 3 44 cm(B) 3 88 cm(C) 3 308 cm(D) 3 616 cm
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Answer: (A) 3 44 cm
Arc length = 36 0 ∘ θ × 2 π r . = 360 60 × 2 × 7 22 × 14 = 6 1 × 88 = 3 44 cm.
If the perimeter and the area of a circle are numerically equal, then the radius of the circle is :
(A) 2 units(B) π units(C) 4 units(D) 2 π units
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Answer: (A) 2 units
2 π r = π r 2 .r = 2 units.
What is the length of arc of a circle of radius 7 cm which subtends an angle of 9 0 ∘ at the centre of the circle ?
(A) 22 cm(B) 11 cm(C) 2 77 cm(D) 2 11 cm
Show answer & solution
Answer: (B) 11 cm
Arc length = 360 90 × 2 × 7 22 × 7 . = 4 1 × 44 = 11 cm.
Area of a quadrant of a circle of radius 7 cm is
(A) 154 cm2 (B) 77 cm2 (C) 2 77 cm2 (D) 4 77 cm2
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Answer: (C) 2 77 cm2
Area of quadrant = 4 1 π r 2 = 4 1 × 7 22 × 7 × 7 = 2 77 cm2 .
What is the length of the arc of the sector of a circle with radius 14 cm and of central angle 9 0 ∘ ?
(A) 22 cm(B) 44 cm(C) 88 cm(D) 11 cm
Show answer & solution
Answer: (A) 22 cm
Arc length = 36 0 ∘ θ × 2 π r = 360 90 × 2 × 7 22 × 14 = 4 1 × 88 = 22 cm
The hour-hand of a clock is 6 cm long. The angle swept by it between 7:20 a.m. and 7:55 a.m. is :
(A) ( 4 35 ) ∘ (B) ( 2 35 ) ∘ (C) 3 5 ∘ (D) 7 0 ∘
Show answer & solution
Answer: (B) ( 2 35 ) ∘
The hour hand turns 3 0 ∘ in 60 minutes, i.e. 2 1 ∘ per minute. From 7:20 to 7:55 is 35 minutes. Angle = 35 × 2 1 = ( 2 35 ) ∘
What is the area of a semi-circle of diameter ‘d’ ?
(A) 16 1 π d 2 (B) 4 1 π d 2 (C) 8 1 π d 2 (D) 2 1 π d 2
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Answer: (C) 8 1 π d 2
Radius = 2 d . Area of semi-circle = 2 1 π ( 2 d ) 2 = 8 1 π d 2
The circumferences of two circles are in the ratio 4 : 5. What is the ratio of their radii ?
(A) 16 : 25(B) 25 : 16(C) 2 : 5 (D) 4 : 5
Show answer & solution
Answer: (D) 4 : 5
2 π r 2 2 π r 1 = 5 4 So r 1 : r 2 = 4 : 5 .
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