by Brad Simmons
Bisecting a Hidden Angle
Use geometer's sketchpad to bisect a hidden angle.
The vertex of angle BAD below is hidden in a region. Within the region, you are not allowed to use a compass or make any constructions other than to draw an angle bisector.
Follow these instructions to bisect angle BAD.
1. Construct lines CE and BD.
2. Construct the bisectors of angle DEC and angle BCE.
3. Label the intersection of the two bisectors as point P.
4. Construct the bisectors of angle BDE and angle DBC.
5. Label the intersection of the two previous bisectors as point Q.
6. Construct line PQ, which bisects the hidden angle.
Please click here for a list of these instructions with illustrations.
Bisect the hidden angle below. Use the method above or devise your own method.
Please click here for the geometer's sketchpad sketch of the figure above.