Draw a perpendicular line from D to line AB. Then draw a perpendicular from D to line BC. Then create a point of intersection where D connects to AB and a point of intersection where D connects to BC. Find the lengths of these two segments that connect D to the sides of the angle.
Move the points around and see what you notice.

Use what you notice to fill in the blanks and add to your notes. Include a picture as well.
An angle bisector divides an ____________ into two congruent parts. Any point on the __________________ is the same distance away from both sides of the ______________________. We measure distance from a point to a line using _________________ segments.