Question

What does the law of cosines reduce to when dealing with a right triangle? A. The Pythagorean theorem B. The formula for a triangle's area C. The law of sines D. The formula for a triangle's area

Answer 1

Cosine law formula is:


`a^(2) = b^(2) + c^(2) - 2*b*c*cos(A)`

where A is an angle opposite from side a.
If angle a is 90 degrees that means that cos(90) is 0 which leaves us with

`a^(2) = b^(2) + c^(2)`

This is Pythagoras theorem where a is the hypothesis and b and c are smaller sides of triangle

Answer is A)