Angle Basics

Angle Basics

By Brian Cox

An angle is a shape formed by two lines or rays that meet or intersect at a common point, called the vertex.

What is an angle?

Angles are measured in degrees.

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A full angle is an angle that has a measure of 360 degrees.

Measures of Angles

Angles are measured in degrees.

A right angle is an angle that has a measure of 90 degrees.

Measures of Angles

Angles are measured in degrees.

A straight angle is an angle that has a measure of 180 degrees.

Measures of Angles

Angles are measured in degrees.

An acute angle is an angle with a measure less than 90 degrees.

Measures of Angles

Angles are measured in degrees.

An obtuse angle is an angle that measures between 90 degrees and 180 degrees.

Measures of Angles

Angles are measured in degrees.

A reflex angle is an angle that measures over 180 degrees.

Measures of Angles

How to Name Angles

How to Name Angles

How to Name Angles

Multiple Select

Identify the correct ways to name the angle shown.

Choose all that apply.

• $$\angle H$$

• $$\angle O$$

• $$\angle HOT$$

• $$\angle THO$$

• $$\angle TOH$$

Multiple Select

Identify the correct ways to name the angle shown.

Choose all that apply.

• $$\angle E$$

• $$\angle D$$

• $$\angle DER$$

• $$\angle RED$$

• $$\angle ERD$$

More Angles

​We often see diagrams where multiple angles share a vertex.

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When this is the case, we are unable to name the angle using only the vertex.

More Angles

​OR

​OR

​Looking at the angles in the diagram separately, name the angle marked in each diagram.

Multiple Select

Identify all correct ways of naming the shaded angle shown.

• $$\angle Q$$

• $$\angle PQR$$

• $$\angle PQS$$

• $$\angle PSQ$$

• $$\angle SQP$$

Multiple Select

Identify all correct ways of naming the shaded angle shown.

• $$\angle X$$

• $$\angle ZXY$$

• $$\angle YXW$$

• $$\angle ZXW$$

• $$\angle YXZ$$

Multiple Select

Identify all correct ways of naming the shaded angle shown.

• $$\angle A$$

• $$\angle TAL$$

• $$\angle ATL$$

• $$\angle TAG$$

• $$\angle LAT$$

Multiple Select

Identify all correct ways of naming the shaded angle shown.

• $$\angle S$$

• $$\angle SJN$$

• $$\angle JSB$$

• $$\angle JSN$$

• $$\angle NSJ$$