CK-12 Geometry - Second Edition

http://www.ck12.org Chapter 12. Rigid Transformations

In this section, our center of rotation will always be theorigin.Rotations can also be clockwise or counterclockwise.
We will only docounterclockwiserotations, to go along with the way the quadrants are numbered.

Investigation 12-1: Drawing a Rotation of 100 ◦

Tools Needed: pencil, paper, protractor, ruler

1. Draw 4 ABCand a pointRoutside the circle.


2. Draw the line segmentRB.


3. Take your protractor, place the center onRand the initial side onRB. Mark a 100◦angle.


4. FindB′such thatRB=RB′.


5. Repeat steps 2-4 with pointsAandC.


6. ConnectA′,B′,andC′to form 4 A′B′C′.