Hi!
You would square the 16 as well as the 20. The equation would be:
20^2=16^2+a^2
You find this by using the equation a^2+b^2=c^2 (a and are the sides and c is the hypotenuse).
*The hypotenuse is always across from the right angle.
So...
20^2=16^2+a^2
400=256+a^2
*subtract 256 from both sides.
You end up with:
144=a^2
Square root both sides.
The a^2 is canceled out.
Your answer is 12.
