a2 + b2 = c2, where c is the opposite side to the right angle called hypotenus and the other two sides are called catheti.
the Pythagorean theorem can be rewritten as:
a = (c2 - b2)1/2
b = (c2 - a2)1/2
c = (a2 + b2)1/2
Example 1 (When two sides are known)
When two of the 3 sides are known in a right triangle the third side can always be determined by using one of the three equations above.
a = 3
b = 4
the hypotenus c can then be determined as followed:
c = (a2 + b2)1/2=(32 + 42)1/2=251/2= 5
Note: If the length of c is twice the length of a, then the angle A and B must be 30o and 60o respectively.