The diameter of a spherical ball is 21 cm. How much leather is require

1.	The diameter of a spherical ball is 21 cm. How much leather is required to prepare 5 such balls?
Answer» Diameter of the spherical ball d’ = 21 cm Thus, its radius r = d/2 = 21/2 = 10/5 cm Surface area of one ball = 4πr² = 4 × 22/7 x 10.5 x 10.5 = 88 × 1.5 × 10.5 = 1386 cm² ∴ Leather required for 5 such balls = 5 × 1386 = 6930 cm²

The diameter of a spherical ball is 21 cm. How much leather is required to prepare 5 such balls?

Answer»

Diameter of the spherical ball d’ = 21 cm

Thus, its radius r = d/2 = 21/2 = 10/5 cm

Surface area of one ball = 4πr²

= 4 × 22/7 x 10.5 x 10.5

= 88 × 1.5 × 10.5 = 1386 cm²

∴ Leather required for 5 such balls

= 5 × 1386 = 6930 cm²