#### Answer

This means that the two sides are $5 \sqrt{10} $ and $ 15 \sqrt{10} $ cm.

#### Work Step by Step

Since one side is three times longer than the other, we will call one side x and the other side 3x. Using the Pythagorean theorem, we have:
$$x^2+ (3x)^2=(50^2)$$
$$x = \sqrt{ \frac{50^2}{10} } = 50/ \sqrt{10}=5 \sqrt{10} $$
This means that the two sides are $5 \sqrt{10} $ and $ 15 \sqrt{10} $ cm.