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

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

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

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

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

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

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

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

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

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

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

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

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