Question 261654
please provide us with more details.. u can use Pythagoras formula..
a^2 + b^2 = c^2

c^2 is the Hypotenuse (the longest one).. 

e.g. 
a^2 + b^2 = c^2

5^2 + 12^2 = c^2

25 + 144 = c^2

169 = c^2

c^2 = 169

c = 13 


but If u want to find Adjacent or opposite site then the formula is 
a^2 = b^2 - C^2

Good luck and hope u understand what I meant..