Question

Question #5aa2c

Answer 1

The law of cosines states that in triangle like the one in the picture below we have that

`c^2=a^2+b^2-2abcosgamma`

Now if `gamma=90^o` which means we have a right triangle we get

from the law of cosines that

`c^2=a^2+b^2-2abcos90=>c^2=a^2+b^2`

which is actually the pythagorean theorem for right triangles.