Right Triangle Trig Formula Sheet

Get the help you or your students need remembering all of the formulas needed for right triangle trigonometry problems with this handy right triangle trig formula sheet.

Background

I usually do a pretty in-depth review of right triangle trigonometry with my precalculus students each year since they usually haven’t seen any trig problems since geometry class a couple of years before.

Occasionally, I have students who skip over geometry, so they have never even heard of SOH CAH TOA before. Last year, I created this right triangle trig formula sheet for them to keep in their binders.

This right triangle trigonometry cheat sheet of sorts helped get all my students on the same page before we started the new fun part of trigonometry in precalculus: the unit circle!

Later in the year, we added a Trig Identities Cheat Sheet to our binders as well.

Right Triangle Trig Formula Sheet

This formula sheet reviews the following topics which form the basics of right triangle trig:

• Parts of a Right Triangle (Adjacent, Opposite, and Hypotenuse)
• Pythagorean Theorem (Also Known as Pythagoras’ Theorem)
• Ratios of Side Lengths for Special Right Triangles (45-45-90 Right Triangle and 30-60-90 Right Triangle)
• Formulas for Three Basic Trig Functions
  • Sin = Opposite / Hypotenuse
  • Cos = Adjacent / Hypotenuse
  • Tan = Opposite / Adjacent
• Formulas for Three Reciprocal Trig Functions
  • Csc = Hypotenuse / Opposite
  • Sec = Hypotenuse / Adjacent
  • Cot = Adjacent / Opposite