Skip to content

Angle Parts and Notation

Run Fullscreen

About This MicroSim

This static diagram teaches the fundamental parts of an angle and proper angle notation. Annotation arrows identify each component, and a notation panel summarizes the different ways to name an angle.

Angle Components

  • Vertex (B) - The common endpoint where both rays meet (orange dot)
  • Side BA - One of the two rays forming the angle (blue)
  • Side BC - The other ray forming the angle (red)
  • Angle Arc - Shows the opening between the rays (green)

Annotations

  • Arrow pointing to B labeled "Vertex"
  • Arrows pointing to each ray labeled "Side BA" and "Side BC"
  • Note explaining that the two rays are the sides of the angle

Angle Notation

Notation Meaning
∠ABC Full angle name (vertex in middle)
∠CBA Same angle, reverse order
∠B Vertex-only notation
m∠ABC = 45° The measure of the angle

Key Rule

The vertex is always in the middle of the angle name!

Learning Objectives

  • Identify the vertex and sides of an angle
  • Apply proper angle notation
  • Understand measurement notation

Bloom's Taxonomy Level

Remembering - Identifying and labeling angle parts.

Iframe Embed Code

<iframe src="https://dmccreary.github.io/geometry-course/sims/angle-parts-notation/main.html"
        height="452px"
        width="100%"
        scrolling="no"></iframe>