Day 4 Angle Bisectors
1) Identify and use angle bisectors in triangles
1) Have students recall what an angle bisector is:
ANGLE BISECTOR - For ray QR to be the angle bisector of <
PQS, point R must be on the interior of < PQS and < PQR
must be congruent to < RQS.
Thus an angle bisector of a triangle is
a segment that separates an angle of the triangle into two congruent
angles. One of the endpoints of an angle bisector is a vertex
of the triangle, and the other endpoint is on the side opposite
2) Together with the students construct the angle bisector
of one angle of the triangle. Have the students construct all
other angle bisectors. Have them compare the relationship of
medians, altitudes, perpendicular bisectors and angle bisectors.
3) Have the students link the definition of triangle angle
bisector with algebra
Practice Problem: In triangle RST, segment
SU is an angle bisector.