Measuring Angles

An angle is formed by two rays (sides) that meet at a common endpoint called the vertex.

The vertex is the point where two lines or rays meet to form an angle.

A right angle measures exactly 90 degrees.

An acute angle is an angle that measures less than 90 degrees.

An obtuse angle is an angle that measures more than 90 degrees but less than 180 degrees.

A straight angle measures exactly 180 degrees.

A full angle measures exactly 360 degrees.

An angle is measured in degrees using a protractor.

The sum of the angles in a triangle is always 180 degrees.

Complementary angles are two angles that add up to 90 degrees.