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

It is reduced to the equation of the Theorem of Pythagoras.

Step-by-step explanation:

Any triangle can be modelled by this formula under the Law of Cosine:

Where:

, , - Side lengths, dimensionless.

- Angle opposed to the side , measured in sexagesimal degrees.

Now, let suppose that angle B is a right angle (90º), so that b is a hypotenuse and a and c are legs. Hence:

And the equation is reduced to the form of the Theorem of Pythagoras, that is to say:

answer: 19 is   2

step-by-step explanation: i just looked at your answer and wrote it down