May 15, 2015

Students understand that the Law of Sines can be used to find missing side lengths in a triangle when you know the measures of the angles and one side length.

Students understand that the Law of Cosines can be used to find a missing side length in a triangle when you know the angle opposite the side and the other two side lengths.

Students solve triangle problems using the Laws of Sines and Cosines.

Teacher and Student versions of full lesson from engageNY

- Mathematics > General
- Mathematics > Geometry

- Grade 9
- Grade 10

Make sense of problems and persevere in solving them.

Reason abstractly and quantitatively.

Use appropriate tools strategically.

Attend to precision.

Look for and make use of structure.

(+) Prove the Laws of Sines and Cosines and use them to solve problems.

(+) Understand and apply the Law of Sines and the Law of Cosines to find unknown measurements in right and non-right triangles (e.g., surveying problems, resultant forces).