This document defines key terms related to angles: An angle is formed by two rays with a common endpoint. Angles are named using the rays and the vertex in the middle. The vertex is the common endpoint of the two rays. Acute angles measure less than 90 degrees, right angles measure 90 degrees, obtuse angles measure between 90 and 180 degrees, and straight angles measure 180 degrees. A protractor is used to measure angles.

1. Name ______________________________________ Date _________________
Mrs. Labuski & Mrs. Rooney Period ___________ Lesson 7-2 Angles
VOCABULARY DEFINTION EXAMPLE
Is formed by two rays •A
with a common endpoint.
Angles are named by the B•
Angle
two rays using the •C
common endpoint in the angle ABC, ∠ABC
middle of the name. angle CBA, ∠CBA
The common endpoint of •A
the two rays.
Vertex The middle point in the B•
name should always be •C
the vertex.
vertex B
Acute angle Measures less than 90°
Right angle Measures exactly 90°
Measures more than 90°
Obtuse angle
and less than 180°
Straight angle Measures exactly 180° • • •
Tool used to measure
Protractor
angles

3. Name ______________________________________ Date _________________
Mrs. Labuski & Mrs. Rooney Period ___________ Lesson 7-2 Angles
VOCABULARY DEFINTION EXAMPLE
•A
Angle B•
•C
angle ABC, ∠ABC
angle CBA, ∠CBA
•A
Vertex B•
•C
vertex B
Acute angle
Right angle
Obtuse angle
Straight angle • • •
Protractor