# Arc Cosine Function

## Function

`arccos(x)`

## Summary

Given a number representing the the ratio of a right triangle's adjacent side over its hypotenuse returns the corresponding angle.

## Input

Name | Description |
---|---|

x | A number from -1 to 1 representing the ratio of the adjacent side over the hypotenuse. |

## Output

Returns the angle corresponding to the ratio.

## Good Links

Angle | concept

Radians | concept

Right Triangle | concept

Cosine | function