Angles

An angle is formed when two lines meet at a point. That point is called a vertex. Angles are measured in units called degrees. A full circle has 360 degrees. Angles help us describe shapes and how things turn.

Types of Angles

There are different kinds of angles. A right angle is exactly 90 degrees and looks like the corner of a square. An acute angle is smaller than 90 degrees, like a slice of pizza. An obtuse angle is larger than 90 degrees but less than 180. A straight angle is 180 degrees and looks like a flat line.

Measuring Angles

We use a tool called a protractor to measure angles. You place the center of the protractor on the vertex and read the number where the line points. Angles are used in building houses, playing sports, and making games. Even the hands of a clock form angles as they move.

Fun Facts

• The three angles inside any triangle always add up to 180 degrees.
• A full turn, like spinning all the way around, is 360 degrees.
• The word angle comes from a Latin word meaning corner.

Did You Know?

When two lines make a right angle, we say they are perpendicular.