Can you use the Cosine Law, c^2=a^2+b^2-2ab.cos C, to find the length of the hypotenuse in a this right triangle if you know the lengths of the legs of the triangle ? Why ?

Question

Can you use the Cosine Law, c^2=a^2+b^2-2ab.cos C, to find the length of the hypotenuse in a	this right triangle if you know the lengths of the legs of the triangle ? Why ?

oobleck · Answer

of course. cos 90º = 0 so now you just have the Pythagorean Theorem.