1. Building Blocks of Geometry
Knowing the basic terms to help build on other ideas in Geometry

2. Points, Lines and Planes
No dimensions, no thickness, gives the location, represented by a dot, use a capital letter to label
Line:
1 dimension, goes in opposite directions forever, goes through at least 2 points, name by using 2 points that are on the line and putting a line symbol above them
Line Segment:
Part of a line, has 2 endpoints, it can be measured, name using two points on the segment with a segment symbol above it
Endpoints – points that start and end a segment

3. Con’t
Ray:
Part of a line, has one endpoint, goes in one direction forever, to name need to have endpoint first and then second point and put the ray symbol above
Plane:
Goes in 2 dimensions, think of coordinate system going on forever in 4 directions, draw it like a rectangle, need at least 3 points for a plane and named using a capital script letter usually written in the corner of the plane
Space:
Goes in 3 dimension, think of length, width and depth, a Kleenex box that continues to go on in every direction

4. Collinear and Coplanar
Need at least 3 points, all of them are on the same line
Noncollinear:
At least three points are not on the same line
Coplanar:
Needs at least 4 points, all of them are on the same plane, points should be noncollinear
NonCoplanar:
At least four points are not on the same plane, points should be noncollinear

5. More Terms Congruent – same length, same measure, symbol ≅
Know symbols for congruent – have same number of markers in the segment or angle
Midpoint – a point that is the same distance from both of the endpoints, middle of the segment, making 2 congruent segments
Bisect – to cut something in half, cut into congruent parts, the midpoint bisects a segment

6. Example
Name a line, ray, segment, collinear points, place, coplanar points

7. Example
Given the picture name a line, ray, segment, state 3 points that are collinear

8. Calculate the Midpoint
What is equation to calculate the midpoint when given coordinates of the endpoint of a segment?
Average of the endpoints

9. Example
Find midpoint of (-8,5) and (3,-6)

10. Could you find an endpoint
If you are given the midpoint and one endpoint could you find the other endpoint.
Sub in what you know and work backwards

11. Con’t
Second part of the formula is how you get the y coordinate of the midpoint
First part of the formula is how you get the x coordinate for the midpoint
Sub in what you know to each of the formulas and work backwards to solve for the other endpoint

12. Example
One endpoint is (2,5) and the midpoint is (-1,3), find the other endpoint.

13. Homework
Pg 33 3,8,18,21,27 Pg 37 1,4,6 Hon 7 Honors Chapter 0 Make a line art or circle art or optical art