AREAS RELATED TO CIRCLES

Question 1

Perimeter of a sector of a circle whose central angle is 90° and radius 7 cm is

(a) 35 cm
(b) 25 cm
(c) 77 cm
(d) 7 cm

Answer 1

(b) 25 cm

Question 2

The area of a circle that can be inscribed in a square of side 10 cm is

(a) 40π cm²
(b) 30π cm²
(c) 100π cm²
(d) 25π cm²

Answer 2

(d) 25π cm²

Question 3

The perimeter of a square circumscribing a circle of radius a units is

(a) 2 units
(b) 4α units
(c) 8α units
(d) 16α units

Answer 3

(c) 8α units

Question 4

The perimeter of the sector with radius 10.5 cm and sector angle 60° is

(a) 32 cm
(b) 23 cm
(c) 41 cm
(d) 11 cm

Answer 4

(a) 32 cm

Question 5

n a circle of diameter 42 cm, if an arc subtends an angle of 60° at the centre, where π = 22/7 then length of arc is

(a) 11 cm
(b) 22/7 cm
(c) 22 cm
(d) 44 cm

Answer 5

(c) 22 cm

Question 6

The perimeter of a sector of radius 5.2 cm is 16.4 cm, the area of the sector is

(a) 31.2 cm²
(b) 15 cm²
(c) 15.6 cm²
(d) 16.6 cm²

Answer 6

(c) 15.6 cm²

Question 7

If the perimeter of a semicircular protractor is 72 cm where π = 227, then the diameter of protractor is

(a) 14 cm
(b) 33 cm
(c) 28 cm
(d) 42 cm

Answer 7

(c) 28 cm

Question 8

If the radius of a circle is doubled, its area becomes

(a) 2 times
(b) 4 times
(c) 8 times
(d) 16 times

Answer 8

(b) 4 times

Question 9

If the sum of the circumferences of two circles with radii R1 and R2 is equal to circumference of a circle of radius R, then

(a) R1 + R2 = R
(b) R1 + R2 > R
(c) R1 + R2 < R
(d) Can’t say;

Answer 9

(a) R1 + R2 = R

Question 10

The perimeter of a circular and square fields are equal. If the area of the square field is 484 m² then the diameter of the circular field is

(a) 14 m
(b) 21 m
(c) 28 m
(d) 7 m

Answer 10

(c) 28 m

Question 11

The radius of sphere is r cm. It is divided into . two equal parts. The whole surface area of two parts will be

(a) 8πr² cm²
(b) 6πr² cm²
(c) 4πr² cm²
(d) 3πr² cm²

Answer 11

(b) 6πr² cm²

Question 12

If the diameter of a semicircular protractor is 14 cm, then its perimeter is .

(a) 27 cm
(b) 36 cm
(c) 18 cm
(d) 9 cm

Answer 12

(b) 36 cm

Question 13

A race track is in the form of a circular ring whose outer and inner circumferences are 396 m and 352 m respectively. The width of the track is

(a) 63 m
(b) 56 m
(c) 7 m
(d) 3.5 m

Answer 13

(c) 7 m

Question 14

The area of the largest square that can be inscribed in a circle of radius 12 cm is

(a) 24 cm²
(b) 249 cm²
(c) 288 cm²
(d) 196√2 cm²

Answer 14

(c) 288 cm²

Question 15

The area of the largest triangle that can be inscribed in a semicircle of radius r is

(a) r²
(b) 2r²
(c) r³
(d) 2r³

Answer 15

(a) r²

Question 16

The area (in cm²) of the circle that can be inscribed in a square of side 8 cm is

(a) 64 π
(b) 16 π
(c) 8 π
(d) 32 π

Answer 16

(b) 16 π

Question 17

If the perimeter of a circle is equal to that of a square, then the ratio of their areas is

(a) 22 : 7
(b) 14 : 11
(c) 7 : 22
(d) 11 : 14

Answer 17

(d) 11 : 14

Question 18

The circumference of two concentric circles forming a ring are 88 cm and 66 cm. Taking π = 22/7, the width of the ring is

(a) 14 cm
(b) 7 cm
(c) 7/2 cm
(d) 21 cm

Answer 18

(c) 7/2 cm

Question 19

A steel wire when bent in the form of a square encloses an area of 121 cm². If the same wire is bent in the form of a circle, then the circumference of the circle is

(a) 88 cm
(b) 44 cm
(c) 22 cm
(d) 11 cm

Answer 19

(b) 44 cm

Question 20

The diameter of a circle whose area is equal to sum of the areas of the two circles of radii 40 cm and 9 cm is

(a) 41 cm
(b) 49 cm
(c) 82 cm
(d) 62 cm

Answer 20

(c) 82 cm