
Rotation  of a polygon
From Latin: rotare  "revolve, roll"
A transformation where a figure is turned about a given point.
Try this
Drag any orange dot to move P, the center of rotation. Drag the polygon to rotate it about P.
The "rotation" transformation is where you turn a figure about a given point (P in the diagram above). The point about which the object is rotated can be
inside the figure or anywhere outside it. The amount of rotation is called the angle of rotation and is measured in degrees.
By convention a rotation counterclockwise is a positive angle, and clockwise is considered a negative angle.
Rays from the point of rotation to any vertex all turn through the same angle as the image is rotated.
Click on "show rays" and rotate the image to see this.
Things to try
In the diagram above  click 'reset'

Rotate the polygon by dragging anywhere inside it. Note how it rotates about the point P.

Drag the the point P inside the polygon. Now when you rotate it, note how it turns around the point P as if P was a pin holding it to the screen.

Rotate the polygon a full 360° and note how it is now back to its original position.

Click "hide details". Then rotate the polygon to some new position and estimate the angle of rotation.
Click "show details" to see how close you got.
Other transformation topics
(C) 2009 Copyright Math Open Reference. All rights reserved

COMMON CORE
Math Open Reference now has a Common Core alignment.
See which resources are available on this site for each element of the Common Core standards.
Check it out
