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Lesson 2: Angle introduction

# Angle basics review

Review what an angle is and how an angle is measured.

### What is an angle?

An angle is two rays that share a start color #11accd, start text, v, e, r, t, e, x, end text, end color #11accd.
One ray extends upward and to the right from point A. A second ray extends downward and to the right from point A.
Intersecting lines or line segments also form angles.
Two lines intersect with each other. One line extends from top to bottom. Another line extends right and slightly upward.
Two segments intersect with each other. One segment extends slightly upward from left to right. A second segment extends upward and to the right from the bottom left.

## Practice: Identifying an angle

Problem 1
Which of the following figures is an angle?

## Measuring angles

Angles are measured in degrees.
The wider an angle is open, the greater its measure. If you compare these two angles, the first one is open wider.
So, the measure of this angle
A ray extends from point A towards between 3 and 4 o'clock. A second ray extends from point A to between 5 and 6 o'clock. A pink arc connects these two rays.
is greater than the measure of this angle.
A ray extends from point B towards between 3 and 4 o'clock. A second ray extends from point B towards 5 o'clock. A pink arc connects these two rays.

## Practice set: Which angle is greater?

Problem 2A
• Current
Which angle measure is greater?