What Is an Angle?
Understand that an angle is a geometric shape formed by two rays sharing a common endpoint (vertex); recognise angles in real-life contexts and 2-D shapes
What a learner can do afterwards
- Identify the vertex and arms of an angle in a diagram
- Find examples of angles in the classroom (e.g. open door, clock hands)
- Explain why two rays meeting at a point form an angle
The lesson
An angle is made from two straight lines called rays. Both rays start from the exact same point. That shared starting point is called the vertex. Each of the two rays is called an arm of the angle.
Look at a triangle. Every corner of the triangle is a vertex, and the two sides that meet there are the arms of an angle. A triangle has three corners, so it has three angles.
You can spot angles all around you, like where a door swings open from its hinge. Just remember: it takes two arms meeting at one shared vertex to make an angle. If the lines do not touch, there is no angle yet.
An angle is the space where two rays meet at one shared point called the vertex.
Watch it
Where it sits
Learn first
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Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.