Hamilton's Math To Build On - copyright 1993

Dividing Angles

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* Dividing Angles

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

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18 September 1995
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