A company manufactures exercise balls for gyms. Type A is a spherical ball with a radius of 12 inches. Type B is a hemisphere that will remain stationary when placed on its base. The radius of the hemisphere is also 12 inches. What is the ratio of the surface area of the sphere to the surface area of the hemisphere?
Accepted Solution
A:
we know that [surface area of sphere]=4πr² [surface area of hemisphere]=2πr²
(sphere) r=12 in [surface area of sphere ]=4π12²--------> 576π in²
(hemisphere) r=12 in[surface area of hemisphere ]=2π12²--------> 288π in²
[the ratio of the surface area of sphere to the surface area of hemisphere] =576π/288π-------> 2