Question

Billy’s exercise ball contains 0.523 m3 of air. What is the radius of the exercise ball? Use 3.14 for π and round your answer to the nearest tenth of a meter.

Answer 1

The radius of exercise ball is 0.5m.

Explanation:

As in general, ball is a sphere. The formula of volume of sphere is, V = 4/3×π×r³ and it is given that the volume of sphere is 0.523m³. Then, you can just substitue the value into the formula :

V = 0.523m³

V = 4/3×π×r³

0.523 = 4/3×π×r³

Next, is to make r as a subject by dividing 4/3 and π :

0.523 = 4/3×π×r³

π×r³ = 0.523÷(4/3)

π×r³ = 0.39225

r³ = 0.39225/π

Now, you can solev it to find the value of r :

r³ = 0.39225/π

r = ∛(0.39225/π)

= 0.5m (near. tenth)

CHECKING :

r = 0.5m

V = 4/3×π×0.4998³ (in working, must give value in more than 3s.f for accurate answer)

= 0.523m³(3s.f)(shown in the question)