Videos and lessons with examples and solutions to help High School students
learn how to make formal geometric constructions with a variety of tools and methods
(compass and straightedge, string, reflective devices, paper folding, dynamic geometric
software, etc.).

Lessons here include:

*Copying a segment; copying an angle; bisecting a segment;
bisecting an angle; constructing perpendicular lines, including
the perpendicular bisector of a line segment; and constructing a
line parallel to a given line through a point not on the line*.

Common Core: HSG-CO.D.12

Basic Geometric Constructions - copying line segments, angles and triangles

How to copy line segments, angles and triangles using a compass and a straight edge.

Bisecting an Angle

How to bisect an angle using a compass and a straight edge.

Constructing a Perpendicular Bisector of a Line Segment

How to construct a perpendicular line bisector using a compass and a straight edge.

Constructing a Line Parallel to a Given Point

How to construct a parallel line through a given point by using a straight edge and a compass.

Bisecting an Angle Efficiently

It is well-known that an angle can be bisected in the traditional way by drawing three arcs. However, it is possible to bisect an angle by drawing two arcs and two lines instead. This Demonstration shows one such method. Two concentric circles are constructed, centered on the angle to be bisected. The intersection of the two lines shown produces the desired bisection.

Bisecting an Angle Efficiently from the Wolfram Demonstrations Project by Nick James

Bisection of Line Segment

Bisect a line segment with compass and straight edge.

Bisection of Line Segment from the Wolfram
Demonstrations Project by Michael Schreiber

Patty Paper - Angle Bisectors

How to fold an angle bisector in a triangle using Patty Paper.

Patty Paper - Perpendicular Bisector

How to fold a midpoint or a perpendicular bisector using Patty Paper

Try the free Mathway calculator and
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