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Angle Bisector

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About This MicroSim

This interactive diagram demonstrates how an angle bisector divides an angle into two congruent (equal) angles. Adjust the slider to change the total angle and see how the bisector always creates two equal halves.

Key Property

If ray BD bisects ∠ABC, then:

\[m\angle ABD = m\angle DBC = \frac{1}{2} \times m\angle ABC\]

How to Use

  1. Drag the slider to adjust the total angle (20° to 160°)
  2. Hover over different parts to see their descriptions
  3. Notice the congruence marks (small arcs) showing equal angles

Color Coding

Color Element
Blue Ray BA and ∠ABD
Red Ray BC and ∠DBC
Green (dashed) Bisector ray BD
Orange Vertex B

Learning Objectives

  • Identify angle bisectors
  • Calculate angle measures using the bisector property
  • Apply the definition: bisector creates two equal angles

Bloom's Taxonomy Level

Applying - Using the bisector property to find angle measures.

Iframe Embed Code

<iframe src="https://dmccreary.github.io/geometry-course/sims/angle-bisector/main.html"
        height="502px"
        width="100%"
        scrolling="no"></iframe>