Holt CA Course Introduction to Geometry Warm Up Warm Up Lesson Presentation California Standards Preview

Holt CA Course Introduction to Geometry Warm Up What geometry term might you associate with each object? 1. one edge of a cardboard box 2. the floor 3. the tip of a pen line segment or line plane or rectangle point

Holt CA Course Introduction to Geometry Preparation for MG2.1 Identify angles as vertical, adjacent, complementary, or supplementary and provide descriptions of these terms. California Standards

Holt CA Course Introduction to Geometry A point is an exact location. It is usually represented as a dot, but it has no size at all. A point A Use a capital letter to name a point. A line is a straight path that extends without end in opposite directions. XY, YX, or l Use two points on the line or a lowercase letter to name a line. X Y l

Holt CA Course Introduction to Geometry A plane is a perfectly flat surface that extends infinitely in all directions. plane QRS Use three points in any order, not on the same line, to name a plane. Q R S

Holt CA Course Introduction to Geometry A ray is a part of a line. It has one endpoint and extends without end in one direction. GH Name the endpoint first when naming a ray. A line segment is part of a line or a ray that extends from one endpoint to another. LM or ML Use the endpoints to name a line segment. L M H G

Holt CA Course Introduction to Geometry Figures are congruent if they have the same shape and size. Line segments are congruent if they have the same length. You can use tick marks to indicate congruent line segments. In the illustration below, line segments AB and BC are congruent.

Holt CA Course Introduction to Geometry Vocabulary point line plane ray line segment congruent

Holt CA Course Introduction to Geometry Identify the figures in the diagram. Additional Example 1: Identifying Points, Lines, and Planes D E F A. three points B. two lines C. a plane D, E, and F DE, DF plane DEF Choose any two points on a line to name the line. Choose any three points, not on the same line to name a plane. Choose any three points.

Holt CA Course Introduction to Geometry Identify the figures in the diagram. Additional Example 2: Identifying Line Segments and Rays A. three rays B. two line segments MN, NM, MO MN, MO Name the endpoint of a ray first. Use the endpoints in any order to name a segment. M N O

Holt CA Course Introduction to Geometry Identify the line segments that are congruent in the figure. Additional Example 3: Identifying Congruent Line Segments AB CD AC BD BF DF EC AE One tick mark Two tick marks Three tick marks The symbol means “ is congruent to.” Reading Math

Holt CA Course Introduction to Geometry Check It Out! Example 1 H I A. four points B. two lines C. a plane H, G, I, and F IH, HF plane IGF Identify the figures in the diagram. G Choose any two points on a line to name the line. Choose any three points, not on the same line to name a plane. F Choose any four points.

Holt CA Course Introduction to Geometry Identify the figures in the diagram. Check It Out! Example 2 A. three rays B. three line segments BC, CA, BD BA, CA, BD Name the endpoint of a ray first. Use the endpoints in any order to name a segment. C AB D

Holt CA Course Introduction to Geometry Check It Out! Example 3 Identify the line segments that are congruent in the figure. AB AC BC DE BD CE One tick mark Two tick marks Three tick marks A B C D E

Holt CA Course Introduction to Geometry Lesson Quiz Identify the figures in the diagram. 1. lines 2. plane Possible answer: plane ABG 3. three rays Possible answer: GA, GB, GC 4. four line segments Possible answer: AG, AD, DG, BG 5. Identify the line segments that are congruent in the figure. AD, BE, CF AG GD, GB GE