# Law of Cosines Worksheets

What is the Law of Cosines? One of the branches of mathematics, which helps in describing the nature of the geometric figure, the triangle is known as trigonometry. There are various laws that help in solving the parts of the triangle which are not known. One of those laws is the law of cosine. The law of cosine is derived from the Pythagoras theorem, with the prospect that it works for all the triangles. The law of cosine is: c2 = a2 + b2 - 2ab cosC
The two other versions of the law of cosines are: a2= c2 + b2 - 2bc cosA
And b2 = a2 + c2 - 2ac cosB.
Since all three versions differ in terms of labeling of the triangle, you can just verify one of them, and you're good to go.

• ### Basic Lesson

Guides students solving equations that involve an Law of Cosines. Demonstrates answer checking. This problem involves all three sides but only one angle of the triangle. This fits the profile for the Law of Cosines.

• ### Intermediate Lesson

Demonstrates how to solve more difficult problems. In &tri;ABC a parallelogram, the adjacent sides measure 40 cm and 22 cm. If the larger angle of the parallelogram measure 116° , find the length of the larger diagonal, to the nearest integer.

• ### Independent Practice 1

A really great activity for allowing students to understand the concept of Law of Cosines. Three sides of a triangle measure 32m, 28m, and 32m. Find the largest angle of the triangle to the nearest degree.

• ### Independent Practice 2

Students find the Law of Cosines in assorted problems. The answers can be found below.

• ### Homework Worksheet

Students are provided with problems to achieve the concepts of Law of Cosines.

• ### Skill Quiz

This tests the students ability to evaluate Law of Cosines.