Finding Sides with Trigonometry
Learning Objective
I can use trigonometric ratios to find missing side lengths of right triangles.
Key Concepts
When solving for missing angles and sides of right triangles, you can use the interior angle sum, SOHCAHTOA, or the Pythagorean theorem.
SOHCAHTOA can be used when you know at least one side length and one non-90 degree angle to find a missing angle or a missing length.
If you know two side lengths of a right triangle, use the Pythagorean theorem to find the third length, then use SOHCAHTOA to find a non-90 degree angle, and finally use the interior angle sum to find the third angle.
Practice Questions
This lesson includes 9 practice questions to reinforce learning.
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1. In a right triangle, if you know the measure of one acute angle, how can you find the measure of the other acute angle?
2. What trigonometric ratio relates the opposite side and the adjacent side of an acute angle in a right triangle?
3. Explain when you would use the Pythagorean Theorem to solve a right triangle problem.
...and 6 more questions
Educational Video
Mastering Right Triangles: Solving for Missing Sides and Angles
JoeCMath