Best Answer

The law of cosines can be written in one form as: c2 = a2 + b2 - 2abCos C.

Without 3 of the 4 variables being given, there is no way to answer this question.

Q: What are the answers to law of cosines in A plus?

Write your answer...

Submit

Still have questions?

Continue Learning about Math & Arithmetic

Trigonometric ratios, by themselves, can only be used for right angled triangles. The law of cosines or the sine law can be used for any triangle.

The law of cosines with a right angle is just the pythagorean theorem. The cosine of 90 degrees is 0. That is why the hypotenuse squared is equal to the sum of both of the legs squared

Yes

It follows from the cyclical symmetry of the cosine rule.

Even though the cosine of an angle was not a known concept at the time, Euclid (3rd century BC) in Egypt stated and proved a pair of propositions which were equivalent to the law of cosines. One proposition was applicable for obtuse angles and the other to acute angles.

Related questions

A caveman from 10,000 BCal-Kashi was the 1st to provide an explicit statement of the law of cosines in a form suitable for triangulation

Trigonometric ratios, by themselves, can only be used for right angled triangles. The law of cosines or the sine law can be used for any triangle.

Law of cosines

The law of cosines with a right angle is just the pythagorean theorem. The cosine of 90 degrees is 0. That is why the hypotenuse squared is equal to the sum of both of the legs squared

cosine = adjacent/hypotenuse

Yes

No, it applies to all triangles.

D. The Pythagorean Theorem

Yes

No, it applies to all triangles.

It follows from the cyclical symmetry of the cosine rule.

We use the law of Cosines to be able to find : 1. The measure of the third side, when the measure of two sides and the included angle of a triangle ABC are known. 2. The measure of any angle, when the measure of the three sides of a triangle ABC are known.