Objectives Identify, name, and draw points, lines, segments, rays, and planes. Apply basic facts about points, lines, and planes.
POINT A POINT is an exact location on a graph, shape or in space. The ball is a POINT on the line.
TO NAME A POINT- WE USE A CAPTIAL LETTER X
LINE A LINE goes in opposite directions and never, ever ends. Take a pearl necklace and stretch it out. The pearls are like points on a line.
TO NAME A LINE- USE ANY 2 POINTS ON THE LINE LINE RT or LINE ST or LINE RS . ST . R T S . RT RS
PLANE A PLANE is a flat surface that goes on forever in all directions. Imagine sitting on an island in the middle of the ocean. No matter which way you look…all you see is water…forever.
PLANE WAG . .A X R .W .G To name a Plane we use 3NONCOLLINEAR Points. 3 points that form a triangle!
POINTS AND LINES CONTAINED IN THE SAME PLANE ARE CALLED COPLANAR Y W. S. P X G.
Points that lie on the same line are collinear Points that lie on the same line are collinear. K, L, and M are collinear. K, L, and N are noncollinear. M K L N
Example 1: Naming Points, Lines, and Planes A. Name four coplanar points. A, B, C, D B. Name three lines. Possible answer: AE, BE, CE
Check It Out! Example 2 Draw and label a ray with endpoint M that contains N. M N
Check It Out! Example 3 Name a plane that contains three noncollinear points. Possible answer: plane GHF
THE INTERSECTION OF 2 LINES IS A POINT . s S IS THE INTERSECTION OF THE 2 LINES
THE INTERSECTION OF 2 PLANES IS A LINE D G B C E E G H C F
Use a dashed line to show the hidden parts of any figure that you are drawing. A dashed line will indicate the part of the figure that is not seen.
Example 4: Representing Intersections A. Sketch two lines intersecting in exactly one point. B. Sketch a figure that shows a line that lies in a plane.
Check It Out! Example 4 Sketch a figure that shows two lines intersect in one point in a plane, but only one of the lines lies in the plane.
Lesson Quiz: Part I 1. Two opposite rays. CB and CD 2. A point on BC. Possible answer: D 3. The intersection of plane N and plane T. Possible answer: BD 4. A plane containing E, D, and B. Plane T
Lesson Quiz: Part II Draw each of the following. 5. a line intersecting a plane at one point 6. a ray with endpoint P that passes through Q