How to Construct an Angle of Fixed
Measure in Geometer’s Sketchpad
Gayle Bynum, Mathematics Educator, MathScience Innovation Center
Developed with funding from the MathScience Innovation Center ©2007
Question
How to construct an angle of fixed measure using Geometer’s Sketchpad
Overview
Occasionally you may wish to create an angle of fixed measure. That is,
constructing an angle in such a way that dragging will not change its measure.
In this activity, you will construct a fixed angle whose measure is 55º.
Materials
The Geometer’s Sketchpad
Procedure
1. Open Sketchpad.
2. Use the POINT TOOL to construct two points,
A and B.
3. Select point A and choose MARK CENTER
from the TRANSFORM menu. Point A is now
marked as the center.
How to Construct a Fixed Angle in Sketchpad - 1
http://MathInScience.info
©MathScience Innovation Center 2007
4. Select point B amd choose
ROTATE from the TRANSLATE
menu. A dialog box will appear.
Click on FIXED ANGLE. Type in
55 for the degree measure of
your fixed angle. Click ROTATE.
Fixed Angle
5. Use the SEGMENT tool to construct
the following segments:
segment between A and B  .
segment between A and B.
How to Construct a Fixed Angle in Sketchpad - 2
http://MathInScience.info
©MathScience Innovation Center 2007