How Do You Find a Missing Side of a Right Triangle Using Cosine?

How Do You Find a Missing Side of a Right Triangle Using Cosine?

Note:

The cosine ratio is not only used to identify a ratio between two sides of a right triangle, but it can also be used to find a missing side length. This tutorial shows you how to use the cosine ratio to find that missing measurement!

Keywords:

  • problem
  • triangle
  • right triangle
  • angle
  • right angle
  • cosine
  • hypotenuse
  • adjacent
  • adjacent side
  • trigonometry
  • trig
  • trig ratio
  • trigonometric ratio
  • ratio
  • cosine ratio
  • leg
  • length
  • find side length
  • find leg length
  • side length
  • leg length

Background Tutorials

  • Ratio Definitions

      • What's a Ratio?What's a Ratio?

      What's a Ratio?

      Ratios are everywhere! The scale on a map or blueprint is a ratio. Ingredients sometimes need to be mixed using ratios such as the ratio of water to cement mix when making cement. Watch this tutorial to learn about ratios. Then think of some ratios you've encountered before!

  • Triangle Definitions

      • What are Acute, Obtuse, and Right Triangles?What are Acute, Obtuse, and Right Triangles?

      What are Acute, Obtuse, and Right Triangles?

      Did you know that there are different kinds of triangles? Knowing how to identify these triangles is an important part of solving many problems involving these triangles. Check out this tutorial and learn about some of the different kinds of triangles!

  • Right Triangles and the Pythagorean Theorem

  • Solving Equations by Multiplying

Further Exploration