Soh-cah-toa

Math

Definition

A mnemonic for remembering the three basic trigonometric ratios in a right triangle. SOH means Sine = Opposite/Hypotenuse, CAH means Cosine = Adjacent/Hypotenuse, and TOA means Tangent = Opposite/Adjacent.

Examples

  • In a right triangle with an angle of 30°, if the hypotenuse is 10, then the opposite side is 10·sin(30°) = 5
  • Finding the height of a building by measuring the angle of elevation and your distance from it using tangent
Key Fact

sin = opp/hyp, cos = adj/hyp, tan = opp/adj

Related Terms

Sine cosine tangent Solving right triangles Pythagorean theorem Angles of elevation and depression

Study This Concept

Practice SOH-CAH-TOA with free review games in these units:

Trigonometry Unit 2: Right Triangle Trigonometry