About Math To Build On ||
On to Marking Angles ||
Back to Perpendicular Lines ||
Angles can be equally divided using a straight edge and a compass.
First: Draw a straight line of any length and a perpendicular line to it Notice that the angles created when you draw perpendicular lines are 90° angles.
Second: Set your compass for a distance less than the shortest line.
Third: Set the compass point at the vertex of the 90° angle and mark all lines. This action gives you three points which are the same distance from the vertex.
Fourth: Place the compass point at each of the three points and mark arcs between the lines.
Fifth: Draw a straight line from each point where the arcs cross, to the vertex of the 90° angle. These lines equally divide the space between the 90° angles, making 45° angles.
Sixth: Measure the angles with your protractor to confirm that the perpendicular lines have been bisected and that two 45° angles have been created.
On to Marking Angles
© 1994- The Math Forum at NCTM. All rights reserved.
Home || The Math Library || Quick Reference || Search || Help
Johnny & Margaret Hamilton
Please direct inquiries to firstname.lastname@example.org
18 September 1995
Web page design by Sarah Seastone for the Geometry Forum