Answer:
r = 12 millimeters
Explanation:
Surface area of a ball = 4πr²
Surface area of a ball = 576 pi square millimeters
Surface area of a ball = 4πr²
576π = 4πr²
r² = 576π / 4π
r² = 144
Find the square root of both sides
√r² = √144
r = 12
r = 12 millimeters