# Rotation of 90 Degrees Counterclockwise

How to solve the rotation of 90 degrees counterclockwise problems: formula, example, and its solution.

## Formula

The image of a point (*x*, *y*),

whose image is under a rotation of 90 degrees

counterclockwise about the origin,

is (-*y*, *x*).

## Example

Rotation of 90º counterclockwise:

(*x*, *y*) → (-*y*, *x*)