if ab is the hypotenuse (the longest side) a^2 + b^2 = c^2....a and b are the legs and c is the hypotenuse 7^2 + 10^2 = c^2 49 + 100 = c^2 149 = c^2...now take sq rt of both sides....this gets rid of the ^2 sq rt 149 = c 12.21 = c
if ab is a leg a^2 + b^2 = c^2 7^2 + b^2 = 10^2 49 + b^2 = 100 b^2 = 100 - 49 b^2 = 51 b = sq rt 51 b = 7.14