Objectives

• Classify angles as acute, right, obtuse or straight.
• Classify angle pairs as supplementary or complementary
• Use real-world angle pair diagrams to find unknown angle measures.

Vocabulary

Acute angle

an angle less than 90 degrees.

Right angle

an angle equal to 90 degrees.

Obtuse angle

an angle greater than 90 degrees but less than 180 degrees.

Straight angle

a straight line equal to 180 degrees

Supplementary angles

two angles whose sum is 180 degrees.

Complementary angles

two angles whose sum is 90 degrees