8.1 Building Blocks of Geometry 6.4.2 I can describe figures by using the terms of geometry

Vocabulary point line plane line segment ray

Use the diagram to name the geometric figure. A. three points V S U W T B. two lines

A. three different line segments Use the diagram to give a possible name to the figure. A. three different line segments C A B B. three ways to name the line

Lesson Quiz Use the diagram to name each geometric figure. 1. three points 2. two lines 3. a point shared by a line and a ray 4. a plane Possible answer: A, B, C Possible answer: AD, CE Possible answer: F Possible answer: plane AEC

8.2 Measuring and Classifying Angles 6.4.2 I can name, measure, draw, and classify angles

Vocabulary angle vertex acute angle right angle obtuse angle straight angle

An acute angle measures greater than 0° and less than 90°. A right angle measures exactly 90°. Right angles are usually marked with a symbol. Reading Math

An obtuse angle measures greater than 90° and less than 180°. A straight angle measures exactly 180°.

Additional Example 3: Classifying Angles Classify each angle as acute, right, obtuse, or straight. A. B. The angle measures less than 90°, so it is an acute angle. The angle measures exactly 90°, so it is a right angle.

The angle measures less than 90°, so it is an acute angle. Check It Out: Example 3 Classify each angle as acute, right, obtuse, or straight. A. B. The angle measures less than 90°, so it is an acute angle. The angle measures exactly 180°, so it is a straight angle.