### A large metal ball with a radius of 15 cm is melted down to make smaller metal balls with a radius of 5 cm. How many of these smaller metal balls can be made?

2 Answers

12/20/2017 5:42:41 PM

Answered by Rhys Lim, a Mathematics with iProTutor

Large metal ball =4/3 (π)(r^3) with r = 15 cm                                 =4/3*3.142*15^3 =14139 cm^3  Small metal ball = 4/3 (π)(r^3) with r = 5 cm                                 =4/3*3.142*5^3 =523.667 cm^3  Number of Small Metal Balls = 14139 / 523.667 = 27 Balls

8/15/2018 1:39:58 PM

Answered by AERON KWEK, a Mathematics with iProTutor

Volume of a large metal ball with R = 15 cm is equal to volume of x metal ball with r = 5 cm So,  4/3 (π)(R^3) = 4/3 (π)(r^3)(x)                    x = (R^3) / (r^3)                       = (15^3) / (5^3)                       = (15/5)^3                       = 3^3                       = 27

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