Three cubes of metal with edges 3 cm, 4 cm and 5 cm respectively are melted to form a single cube. Find the lateral surface area of the new cube formed.
Given,
Edge of three cubes a1 = 3 cm , a2 = 4 cm , a3 = 5 cm
Let edge of single cube formed = A cm
Sum of volume of three cubes = volume of single cube formed
= a13 + a23 + a33 = A3
= 33 + 43 + 53 = A3
A3 = 27 + 64 + 125 = 216
A = 
Lateral surface area of new cube = 4a2 = 4 × 6 × 6 = 144 cm2
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