Segment Bisector

Often in geometry, we use the properties of figures in order to construct them.  Constructions are different from drawings because we use a tool called a compass and a straightedge (like a ruler, but without measurements) to create them.  The first construction you will learn is a segment bisector.  When we bisect something, we cut it in half, so we will be cutting a segment in half.  You will learn in later lessons which properties make this construction possible.

Assume that segment AB is given. To bisect segment AB follow the steps shown below.

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An alternative to compass and straightedge construction is paper folding. If you draw a line segment on tracing paper, then fold the segment onto itself so that the endpoints are on top of one another, you will have constructed a segment bisector.