Law of Cosines
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The law of cosines is a formula relating the side lengths and angles of a general triangle which is a generalization of the Pythagorean theorem.
Law of cosines is a high school-level concept that would be first encountered in a trigonometry course. It is listed in the California State Standards for Trigonometry.
Prerequisites
| Cosine: | The cosine is the ratio of the length of an angle's adjacent side to the length of the hypotenuse in a right triangle. |
| Pythagorean Theorem: | The Pythagorean theorem is an equation relating the lengths of the sides of a right triangle as a squared plus b squared equals c squared, where c is the length of the hypotenuse. |
| Triangle: | A triangle is a three-sided (and three-angled) polygon. |
| Trigonometry: | Trigonometry is the study of angles and of the angular relationships of planar and three-dimensional figures. |