Question 6619
In this case you can simply use Pythagoras, which states that the length of both sides of a right triangle squared and then added together will give you the length of the hypotenuse squared. In mathematic terms this means: let 'a' and 'b' be the two sides of the right triangle and 'c' the hypotenuse: a^2 + b^2 = c^2. You can use this rule to determine the length of 'the other side' in your question.

5.21^2 + 9.13^2 = 110.501
110.501 = c^2
c = 10.5

Hope that helps.
Regards,
-Mike