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.

The area of a circle is 394.24 cm². Calculate :

(i) the radius of the circle,

(ii) the circumference of the circle.

The perimeter of a semi-circular metallic plate is 86.4 cm. Calculate the radius and area of the plate.

The circumference of a circle exceeds its diameter by 180 cm. Calculate :

(i) the radius

(ii) the circumference and

(iii) the area of the circle.