Three metal cubes with edge lengths of 9 cm, 12 cm, and 15 cm are melted and recast into a single cube. What is the edge length of the new cube?

Explanation

To find the edge of the new cube, first calculate the total volume by summing the volumes of the three cubes: 9³ + 12³ + 15³ = 729 + 1728 + 3375 = 5832 cm³. The edge length of the new cube is the cube root of 5832, which is 18 cm.