What does the law of cosines reduce to when dealing with a right triangle?

Makeba: 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 cosines cannot be applied to a right triangle
D. The law of sines

Answers and Views:

Answer by the mathemagician
c^2 = a^2 + b^2 – 2ab cos C

When C is a right angle

c^2 = a^2 + b^2

Look familiar ?

love and kisses,

Pythagoras

Answer by Suzie s
WE USE THE LAW OF COSINES AND THE LAW OF SINES to solve triangles that are not right-angled. Such triangles are called oblique triangles. The Law of Cosines .

Right triangle.

Answer by Philo
reduces to the Pythagorean Theorem, since cos Θ = 0 when Θ = 90°, so the -2ab cos Θ term becomes 0, and so c² = a² + b² – 2ab cos Θ → c² = a² + b² + 0 → c² = a² + b²

Answer by asymptote
As the mathemagician and Philo have said, it reduces to the Pythagorean theorem… but only when the enclosed angle is the right angle! So your question should more accurately read something like:

“What does the law of cosines reduce to when the enclosed angle is a right angle?”