**SOH-CAH-TOA**

This simple mnemonic (which bears a resemblance to a Native American name) is used to remember how to compute the sine, cosine and tangent of a right-angled triangle and the relationships between them.

When labeling a triangle, it is imperative to take note of the following parts:

- Hypotenuse (H) - the longest side of the triangle
- Angle (θ) - theta is often used to name the acute angle of a triangle one’s trying to find the sine/cosine/tangent of, however this is not always the case; any consistent labeling is fine
- Adjacent (A) - the side of the triangle next to the selected angle
- Opposite (O) - the side of the triangle opposite the selected angle

Note: Do not think that the way the pictured triangle above is the only way you can label a triangle. The opposite and adjacent can easily switch places if the other angle is selected!

Opposite
Sin θ = -----------------
Adjacent

Adjacent
Cos θ = -----------------
Hypotenuse

Opposite
Tan θ = -----------------
Hypotenuse