What’s on the Menu Today? Daily Warm Up Turn in and go over homework questions 1.2 Notes on Basic Geometric Terms Basic Definitions Work Sheet
Warm It Up #1 Using what you learned about the Three Steps to Reason, make a conjecture about the first 100 positive even integers. Share your conjecture with a friend. Do you think this conjecture is valid? If so, why? If not, why not? 2 is the only prime number in the first 100 positive even integers The last number is actually 200 since there are 50 evens in the first 100 and 50 evens in the second.
Section 1.2: Basic Geometric Terms Identifying Geometric Terms in Real Life Section 1.2: Basic Geometric Terms
Definition: Point A point has no dimension and is usually represented by a small dot. Point A . A
Definition: Line A line extends without end in two directions. It is usually represented by a straight line with two arrowheads (symbolized by AB) Collinear Points: two points that lie on the same line. Example: A and B are collinear points
Definition: Line Segment A Line Segment is the part of a line ending at two specific points and all the points between the two endpoints. (Notice there are no arrows at the end) A B
Definition: Ray & Initial Point The ray AB (symbolized by AB) consists of the initial point A and all points on AB that lie on the same side of A as point B. IMPORTANT: the first letter must indicate the starting point of the ray.
Definition: Opposite Rays Opposite Rays share a common initial point, but point opposite directions. If C is between A and B, then CA and CB are opposite rays. Any two opposite rays are collinear. A C B
Recap Line Segment Ray Opposite Ray Draw what they look like and how to denote them in the boxes
. A plane extends in two dimensions. It is usually represented by a shape that looks like a table or a wall, however you must imagine that the plane extends without end
Definition: Coplanar Points Coplanar points are points that lie on the same plane. Call it: Plane M or plane ABC Note: points A,B,C are coplanar points. .A .B .C M
Definition: Intersect Geometric figures are said to intersect if they have one or more points in common. The intersection of the figures is the set of points the figures have in common. How many points of intersection do these lines have in common?
Your Turn EX: Sketch a line that intersects a plane at one point. Solution: Draw a plane and a line Emphasize the point where they meet Dashes show where the line is hidden by the plane.
Your Turn Ex: Sketch two planes whose intersections form a line. Solution: Draw two planes Emphasize the line where they meet. Dashes indicate that one plane is hidden by the other.
Intersecting “planes”
Homework P. 13 # 3 - 67 Odd, 73 - 75