Step-by-step explanation:
I assume the ball is solid too.
so, both objects must have the same volume.
the volume of the cylinder is
base area × height = pi×7² × 5 = 49pi × 5 = 245pi =
= 769.6902001... cm³
the volume of the ball is
4/3 × pi×r³ = 245pi
4/3 × r³ = 245
4×r³ = 735
r³ = 735/4 = 183.75
r = cubic root(183.75) = 5.685156826... ≈ 5.69 cm
