Describing a Rotation requires 3 things;
a) its centre,
b) angle and
c) direction (clockwise/anti-clockwise -- refer to the way a clock rotates)

This page is determined to kill 2 birds with one stone.

CONCEPT 1 -- How objects are rotated

A) Click button 5 to reveal the centre of rotation.  Move the centre anywhere and click 'Animate' to discover how the image of an object rotates (given different centre and angle).  You can also rotate it manually.

B) What happens when the centre of rotaion is on the object itself?

Sorry, this page requires a Java-compatible web browser.

CONCEPT 2 -- How do you find Center of Rotation given the object and image.

1. Click on buttons 1 to 5 to learn the steps to finding the centre of rotation.
2. Click "Clear & Try Again" 
3. Drag points A, B or C to resize the object.  Repeat.