Pythagoras' Theorem
a^2+b^2=c^2
c is the longest side of the triangle
a and b are the other two sides
In a right angled triangle:
the square of the hypotenuse is equal to
the sum of the squares of the other two sides.
[tex]c = \sqrt{ {4 }^{2} + 3 { }^{2} } \\ c = \sqrt{16 + 9} \\ c = \sqrt{25} \\ c = 5[/tex]