EMAT 6700

by Brad Simmons

Reflecting a Triangle

Use geometer's sketchpad to reflect a triangle over a line.

Construct the reflected image of triangle ABC over line m.

1. Since point A is on line m, point A is its own reflection.  Construct perpendiculars from point B and point C through line m.

2.  Locate point Y and point Z so that line m is the perpendicular bisector of segment BY and segment CZ.  Points Y and Z are the reflected points of B and C.

3.  Hide the construction objects.  Connect vertices A, Y, and Z.

Since points A, Y, and Z are reflected images of points A, B, and C, triangle AYZ is the reflection of triangle ABC.

Please click here for a geometer's sketchpad sketch of the figure shown above.