Monday, August 1, 2011

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

Cos θ = -----------------

Hypotenuse

```
```              Opposite

Tan θ = -----------------

Hypotenuse```

### Notes

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I LOVE THEM REALLY.
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