August 25, 2014 -Take out a pencil and prepare for your first warm-up Essential Question: What are the building blocks of geometry?
Warm-Up Looking at the pictures below, write a short description of what an “Ork” is. Now choose: Which one of the four would be considered an Ork? Orks all have curved bodies. They also have at least one tail. They all have the black dot inside.
Writing Assignment • Write a paragraph to answer the following questions: • What makes a good definition? • Why do we need to know our definitions? • What would be an example of a bad definition? • Why are definitions important in a Geometry class?
Definitions • Point: It has location and nothing else. No size. No height. No depth. No friends. The basic unit of geometry. Capital Letters are used. • Line:A straight, unbroken set of points that goes on forever. It has infinite length but no thickness. Point A h Look at the notation, above the letters are symbols that look like lines We can also use one letter. This one is lowercase and in script Line h
Definitions M A • Plane : a surface that has length and width but no thickness. It is a flat surface that extends forever. • Line Segment: A line that has two endpoints • Ray: A line that contains only ONE endpoint. B C plane M Plane ABC See how the notation uses a line segment without arrows on the ends. Once again, notice the notation uses a symbol that looks like a ray.
Definitions • What are some words that have the prefix co-? • What does that prefix mean? • Collinear: • On the same line • Coplanar: • On the same plane M A B C
Last Definition! • Angle: two rays that share a common endpoint, provided the two rays do not lie on the same line. That common endpoint is known as the vertex. D E F Note: If there was another line coming out of the vertex, you cannot name the angle by the vertex since it represents too many angles.
Physical Models in Real Life Point Line Plane
Physical Models in Real Life Angle Ray
Exit Slip Write your answers on a half sheet of paper. • If two planes intersect, what does the intersection look like? • If two lines intersect, what does the intersection look like? • If a line an a plane intersect, what does the intersection look like? • Name another real-life example of a plane and an angle. • Does plane ADQP exist in the following picture?