The area between two concentric circles having radii 70 cm and 50 cm is:

The area of a circle is increased by 22cm² , when its radius is increased by 1 cm. The original radius of the circle is:

If the ratio of the radii of the two wheel is 3 : 4 , then the ratio of their circumference is:

If the perimeter and area of a circle are numerically equal , then the radius of the circle is:

The perimeter of a sector of angle 45^o of a circle with radius 7 cm is:

The perimeters of a circular and a square field are equal. If the area of the square field is 484 m², then the diameter of the circular field is:

A chord of a circle of radius 14 cm subtends 60^o at the centre. Then , the area of the major sector is:

If an arc makes an angles of 72^o at the centre of a circle of radius 10 cm, then its length is:

The length of the rope by which a cow must be tethered so as to graze an area of 9856 m² is :

If the perimeter of a semicircular protractor is 36 cm , then its diameter is: