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