This theorem proves that for a right angle triangle, the area of the square on the hypothenuse (the longest side or the side opposite the right angle) is equal to the sum of the area of the squares on the sides adjacent to the right angle.
Once we have established the area of the square we can then take the square root of this to give us the length of one side of the square thus providing us with the length of one side or the triangle.
Now suppose we have a right angle triangle (figure 1) then the formulae to calculate this would be:
Illustration of Formula
Figure 3 below illustrates how this formula works in practice. The area of the two squares adjacent to the right angle combined will equal the area of the square adjacent to the hypothenuse.
We can now apply our formulae to figure 2 :
+ = (then solve for c)
= 9 + 16
c = 5