A sheet is 11 cm long and 2 cm wide. Circular pieces 0.5 cm in diameter are cut from it to prepare discs. Calculate the number of discs that can be prepared.

Find the circumference and area of a circle of radius 15 cm.

The circumference of a circle is 123.2 cm. Calculate :

(i) the radius of the circle in cm;

(ii) the area of the circle to the nearest cm²;

(iii) the effect on the area of the circle if the radius is doubled.

Find the length of a rope by which a cow must be tethered in order that it may be able to graze an area of 9856 m².