#### Belonging to important branch mathematics is trigonometry, which helps in determining the nature of a triangle. To do that, there are different laws that can help you in the process. One of the most important laws is the Pythagoras theorem, which is also a law that helps in determining other laws; the law of cosine is one of them. This law works on all parts of the triangle. It only depends on which information of the triangle is given to you.
The law of cosine is: c^{2} = a^{2} +b^{2} - 2ab cos C.
The two other versions of the law of cosines are: a^{2} =c^{2} +b^{2} - 2bc cos A. And b^{2} =a^{2} +c^{2} -2ac cos B. Since all three versions differ in terms of labeling of the triangle, you can just verify one of them, and you are good to go. The Law of Cosines involves the relation of the lengths of the sides of a triangle to the cosine of one of its angles.

In these worksheets, students will use the law of cosines to solve problems. Problems are presented as word problems, and students will be required to write the problem as an equation and then solve. Extra paper may be required in order for students to do their calculations. Some worksheets also include a diagram of a triangle for student reference in solving the problems. This set of worksheets contains step-by-step solutions to sample problems, both simple and more complex problems, a review, and a quiz. It also includes ample worksheets for students to practice independently. Most worksheets contain between eight and ten problems. When finished with this set of worksheets, students will be able to solve word problems using the Law of Cosines. These worksheets explain how to use the Law of cosines. Sample problems are solved and practice problems are provided.