# How do you know what trigonometric function to use to solve right triangles?

##### 1 Answer

Right triangles are a special case of triangles. You always know at least one angle, the right angle, and depending on what else you know, you can solve the rest of the triangle with fairly simple formulas.

If you know any one side and one angle, or any two sides, you can use the pneumonic **soh-cah-toa** to remember which trig function to use to solve for others.

**Opposite** refers to the side which is not part of the angle, **adjacent** refers to the side that is part of the angle, and the **hypotenuse** is the side opposite the right angle, which is

For example,lets say you know the length of

Which rearranges to;

If you know the length of both sides

Then you take the inverse tangent,