1. 1.1 Building Blocks of Geometry

2. Identifying lines, rays, and segments
VOCABULARY
Point – usually labeled with an uppercase letter. Describes a specific location in space.
Line – points that extend without end in two opposite directions
Read as: “line NO or line ON” N O
Symbol:
NO or ON
Ray – has one endpoint and extends without end in one direction. Always when naming give the endpoint first.
Read as: “ray AB” B A
Symbol: AB

3. Identifying lines, rays, and segments continued….
Segment – a piece of a line which has two endpoints
Read as: “line segment BE or
line segment EB” ● ●
Symbol:
BE or EB B E
NOTE: You may have the points at the end of the segment or without.
Plane – flat surface that extends indefinitely along its length and width
Read as: plane ABC

4. Identifying lines, rays, and segments continued….
Parallel lines – two different lines that will never intersect no matter how far they extend. C
“Line CD is parallel to line YZ.” D Y
CD | | YZ Z
Intersecting lines – two different lines that meet at a point Q T
“Line TS intersects with line PQ” S P

5. Let’s Do Some Examples! Identify and name the line, ray, or segment. SQ P 1. 2. ● ● 3. N R
ray
line segment
line
QP or PQ
RS or SR
MN or NM

6. Now You Try! Identify and name the line, ray, or segment. G ray
GF or FG F
line
HJ or JH J H L
segment
KL or LK K ● ●

7. Now You Try Continued G H J K L 1. Name 2 rays. HL or GK or JL or JK
Name 2 segments that have G as an endpoint.
GH and GJ
3. Name a line. GH
4. Name 3 points.
Any 3 that includes L or J or K or H or G

8. Now You Try Continued G A B C D F E
1. Name a pair of intersecting lines.
AB and EG or CF and EG
2. Name a pair of parallel lines.
AB and CF
3. Name DB and BA another way.
BD and AB

9. Midpoint
Midpoint – The midpoint of a segment is the point on the segment that is the same distance from both endpoints.
Bisects – The midpoint bisects the segment, meaning that it divides it into two congruent segments
M is the midpoint of AB.

10. 1.2 Angles

11. What is an angle?
Angle – An angle is formed by two rays that share a common endpoint
Vertex – The common endpoint of the two rays
Sides – The two rays
Point B is the vertex of angle ABC.
The angle may also be referred to as angle CBA, angle B,
, or

12. Angle measures
Angle measures – can be anywhere between 0 and 180 degrees.
“The measure of angle A is 45 degrees”

13. Using a protractor Place hole in center of protractor on vertex
Align first ray along line on bottom of protractor
Use other ray to find angle measure