Question 1085090

This was a question on my cct part 2 and i did not understand it at all.

Find the length of the other two sides of a right angle triangle if the hypotenuse is 15cm and one side is 3cm longer than the other side.
<pre>{{{highlight_green(matrix(1,4, 12, and, 9, cm))}}}
This triangle represents a 3-4-5 Pythag. triple, TIMES 3.