The difference between the radii of the smaller circle and the bigger circle is 7cm and the difference between the areas of the two circles is 1078 cm². Then , the radius of the smaller circle is

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

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

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

If the perimeter of a semicircular protractor is 36 cm , then its diameter 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 ratio of the radii of the two wheel is 3 : 4 , then the ratio of their circumference is:

If the circumference of a circle is 66 cm , then the area of the circle is

A  horse is tied to a pole with 28 m long string. The area where the horse can graze is:

The length of a minor arc is ²/9 of the circumference of the circle. Then , the measure of the angle subtended by the arc at the centre of the circle is: