sq cm. of sheet is required to make a hemispherical bowl. Let us write by calculating the length of diameter of the forepart of the bowl.

Let us write whether the following statements are true of false.

i. If we double the length of radius of a solid sphere, the volume of sphere will be doubled.

ii. If the ratio of curved surface areas of two hemispheres is 4 : 9, the ratio of their lengths of radii is 2 : 3.

The whole surface area of a solid hemisphere with length of 7 cm radius is

Let us fill in the blanks.

i. The name of solid which is composed of only one surface is _______.

ii. The number of surfaces of a solid hemisphere is ___________.

iii. If the length of radius of a solid hemisphere is 2r units, its whole surface area is __________ π r² sq units.

Whole surface area of a solid hemisphere is equal to the curved surface area of the solid sphere. Let us write the ratio of lengths of radius of hemisphere and sphere.

If the length of radius of a sphere is 10.5 cm., let us write by calculating the whole surface area of the sphere.

If the length of radius of a sphere is increased by 50%, let us write how much percent will be increased of its curved surface area.

The curved surface area of a solid sphere is equal to the surface area of a solid right circular cylinder. The lengths of both height and diameter of cylinder are 12 cm. Let us write the length of radius of the sphere.

The length of diameter of base of a hemispherical tomb is 42 dm. Let us write by calculating the cost of colouring the upper surface of the tomb at the rate of ` 35 per square metre.

If the cost of making a leather ball is 431.20 at 17.50 per square cm., let us write by calculating the length of diameter of the ball.