Properties of the Angle Bisector
📐 What is an Angle Bisector?
An angle bisector is a ray that divides an angle into two equal parts. If ray $BD$ bisects $\angle ABC$, then:
$$\angle ABD = \angle DBC = \frac{1}{2} \angle ABC$$
Think of it like folding an angle exactly in half — the crease line is the angle bisector!
⭐ Key Property 1: Equal Angles
The most fundamental property: an angle bisector creates two congruent angles.
If $\angle ABC = 80°$ and $BD$ bisects it, then:
- $\angle ABD = 40°$
- $\angle DBC = 40°$
Interactive visualization — available in the full lesson