The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3?

Given that,
The diameter of a metallic ball is 4.2 cm.
The density of the metal is 8.9 g/cm³
To find out,
The mass of the ball.
We know that,
Mass = Volume × Density
Also, a ball is spherical in shape.
And, volume of a sphere = (4/3)πr³
Here, r = 4.2/2 = 2.1 cm
Hence, volume of the ball = (4/3) × (22/7) × (2.1)³ [≈ π = 22/7]
= 814.97/21 = 38.81 cm³
So, mass of the ball = 38.81 × 8.9 = 345.41 g
Hence, the mass of the ball is 345.41 g.