1. A wheel makes 4000 revolutions in moving a distance of 44 km. Find the radius of the wheel.
2. If the area of a semi-circle be 77 sq m, find its perimeter.
3. The area of a sector of a circle of radius 36 cm is 72πcm2. The length of the corresponding arc of the sector is
4. If the radius of a circle is increased by 6%, find the percentage increase in its area.
5. The area of a sector of a circle is 77 sq cm and the angle of the sector is 45°. Find the radius of the circle.
6. The ratio of the areas of the circumcircle and the incircle of a square is
7. The area of a circle is increased by 22 sq cm when its radius is increased by 1 cm. Find the original radius of the circle.
8. Find the length of a rope by which a cow must be tethered in order that may be able to graze an area of 154 sq m.
9. What is the area of the larger segment of circle formed by a chord of, length 5 cm subtending an angle of 90° at the centre?
10. A man riding a bicycle, completes one lap of a circular field along its circumference at the speed of 14.4 km/h in 1 min 28 s. What is the area of the field ?
11. A person observed that he required 30 s time to cross a circular ground along its diameter than to cover it once along the boundary. If his speed was 30m/min, then the radius of the circular ground is (take π = 22/7)
12. What is the total area of three equilateral triangles inscribed in a semi-circle of radius 2cm ?
13. How many circular plates of diameter d be taken out of a square plate of side 2d with minimum loss of material?
14. What is the area of a circle whose area is equal to that of a triangle with sides 7 cm, 24 cm and 25 cm ?
15. A circle of radius 10 cm has an equilateral triangle inscribed in it. The length of the perpendicular drawn from the centre to any side of the triangle is