35. How much leather is needed to sew a ball
with a diameter of 13.1 inches, if an extra
10% of the material is needed for the seams?

593.04 square inches leather is needed.

Step-by-step explanation:

Leather needed to sew a ball = Surface area of the ball

Surface area of the sphere = 4πr²

                                             = 4π(6.55)²

                                             = 539.13 inches²

Since 10% extra material is needed for the seams, amount of material required = 539.13 + (10% of 539.13)

= 593.043

= 593.04 square inches

593.04 square inches of leather will be needed.