Q5 of 64 Page 77

Three metallic cubes of side 3 cm, 4 cm and 5 cm respectively are melted and are recast into a single cube. Find the total surface area of the new cube.

Given:

three cubes of side 3 cm, 4 cm and 5cm


Total volume of all cube = volume of new cube


(3)3 + (4)3 + (5)3 = (a)3


27 + 64 + 125 = (a)3


216 = (a)3


⇒ a = 6


TSA of cube = 6a2


= 6(6)2


⇒ TSA of cube = 216cm2


More from this chapter

All 64 →
3

A container is in the shape of a cube of side 20 cm. How much sugar can it hold?

 4

A cubical tank can hold 64,000 litres of water. Find the length of the side of the tank.

 6

How many cubes of side 3 cm are required to build a cube of side 15 cm?

 7

Find the area of card board required to make an open cubical box of side 40 cm. Also find the volume of the box.