# 1.5: Trigonometry Functions

- Page ID
- 2635

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When determining the designate angle we can use different ratios of sides.

- We can use a ratio of the opposite to the hypotenuse.
- We can use a ratio of the adjacent to the hypotenuse.
- We can use a ration of the opposite to the adjacent.

Each ratio has a trigonometric function that helps turn the ratio into an angle. They are:

- sin θ = opposite/hypotenuse
- cos θ = adjacent/hypotenuse
- tan θ = opposite/adjacent

One way of remembering the ratios are these mnemonics:

- SOH – Sine is opposite/ hypotenuse
- CAH – Cosine is adjacent/hypotenuse
- TOA – Tangent is opposite/ adjacent

By the way,

- sin is short for sine
- cos is short for cosine
- tan is short for tangent

**Video!**

This video walks through how to determine the angle of a right triangle when you have two sides.