A right triangle has a leg that is 3 in long, and a hypotenuse that is 5 in long. Find the length of the other leg of this triangle.

According to Pythagoras theorem

Hypotenuse square = altitude square + base square

By substituting the values

5 square = 3 square + base square

25 = 9+base square

25 - 9 = base square

16 = base square

base = root 16

=4