BUILDING BLOCKS OF GEOMETRY

WOOOOOOT!

GEO-METRY

◦Geo=earth

◦Metry=measure

Building Blocks of Geometry

◦Undefined Terms◦“It’s kinda like…”

◦Point◦Line◦Plane

◦Defined Terms◦Defined using undefined terms

Undefined Terms

Point Plane

Line

INVESTIGATION

Step 1 Identify examples of points, lines, and planes in these pictures.

Step 2 Explain in your own words what point, line, and plane mean.

www.aaccessmaps.com John Rogers—www.visualistimages.com

Defined Terms◦Some defined terms are pretty obvious

◦Coplanar, collinear, line segment, endpoint, midpoint

◦Some aren’t…◦Congruent ◦bisect ◦Ray

Take a few moments to define the easy ones.

1.Name three tennis balls that are collinear.

2.Name three that are coplanar but NOT collinear.

3.Name four that are NOT coplanar.

Ball A is in the pocket of the man. Ball C is on the woman’s racquet. All other balls are on the tennis court.

Those Not So Obvious Words

◦Congruent◦Things are congruent if (and only if) they have equal measures.

◦Bisect◦Divide a segment into two congruent segments.

◦Ray◦A ray is like a line, but only goes on in one direction (instead of two directions).

Notation: How We Write

◦How many points do we need to name to identify a…◦Point?◦Line?◦Plane?

Notation

◦Never assume more than what is written!!!

What makes a good definition?◦Concise

◦Includes all necessary information and NOTHING ELSE!

◦What should we include when we make our definitions?◦The verbal definition◦Characteristics◦Examples (Don’t forget pictures!)◦Non-examples (Don’t forget pictures!)

Vocabulary

◦Collinear

◦Coplanar

◦Line Segment

◦Endpoint

◦Congruent Segments

◦Midpoint

◦Bisect

◦Ray

◦Point*

◦Line*

◦Plane*