# Unit 1: ```Day 1 – Understanding Points, Lines, and Planes
The most basic figures in geometry are the point, line, and plane.
They are considered to be undefined terms, which cannot be defined by using other
figures.
TERM
NAME
DIAGRAM
Point
Line
Plane
Points that lie on the same line are collinear.
Points that lie on the same plane are coplanar.
The points A, B, C, and D are coplanar. The points A, B, C, and E are noncoplanar.
Day 1 – Understanding Points, Lines, and Planes
TERM
NAME
DIAGRAM
Segment
Endpoint
Ray
Opposite
Rays
Questions
1. Using the diagram at the right, answer the following.
a. Give another name for plane N.
b. Give three other names for BC .
m
c. Name 3 collinear points.
,
,
d. Are B, C, D, and E are coplanar?
e. Is BC the same figure as BD ?
f. Name a pair of opposite rays in the figure.
2. Draw and label a segment with endpoints M and N.
3. Sketch the following.
a. a line that intersects two nonintersecting planes
b. Three lines intersecting at three
different points.
```