# Angle Bisectors of a Triangle

Topic:
Angles
Discover properties of angle bisectors
Part 1 1) BD is an angle bisector of <ABC. Drag point C around. Write a definition for angle bisector based on your observations. 2) Drag points A and B around. Does your definition from #1 hold true? 3) Click: Show segments from angle bisector 4. Drag point D, what can you conclude about points on the angle bisector? Part 2 5. Click: Show Segment AC and Show 2nd Angle Bisector 6. Are the properties you found of angle bisector Line BD also true of angle bisector Line CG? Part 3 7. Click: Show 3rd Angle Bisector 8. What do you notice about the 3 angle bisectors? 9. Drag the 3 vertices of the triangle (A, B and C). Do the angle bisectors always intersect? Do they ever intersect outside of the triangle? 10. Drag points D and G to the intersection of the 3 angle bisectors. What do you notice about the 3 segments perpendicular to the sides of the triangle? Write a conclusion about what you learned through this lab.