Problem #PRU-5023

Problem

Let $a$ and $b$ be positive real numbers. Using volumes of cubes and parallelepipeds, show that $(a + b)^{3} = a^{3} + 3 a^{2} b + 3 a b^{2} + b^{3}$ .
Hint: Place the cubes with sides $a$ and $b$ along the same diagonal.

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