Section 1.1 By Mia Gurganus and Lauren Archibald

Points  A point is a dot named with a capital letter.  Ex. M A Z K

Lines  A line is made up of points that are straight.  Lines are named after any two points on it. (Hint: Lines have arrows on the ends of them to indicate that they go on forever in both directions)  Ex. 2. M N 1. A B 3. G J Line 1: AB Line 2: NM Line 3: GJ

Line Segments and Rays  Line segments are made up of points, are straight, and have a definite beginning and end. B  Rays are made up of points and are straight. A ray begins at an endpoint and extends infinitely far in only one direction. Rays must be named with the endpoint first so it is clear where the ray begins. A B This ray can only be represented as AB A The segment could be represented as AB or BA

Number Lines  A number line forms after a numerical value is assigned to each point on the line.  Ex. F P The coordinate of F is 0. The coordinate of P is 3.

Angles  An angle is the union of two rays with a common endpoint.  The point where the two rays meet is called the vertex of the angle.  The rays are called sides of the angle.  When naming an angle, three letters are used. The vertex letter must be named in the middle. You could also simply name the angle by the vertex point’s letter. G M H This angle could be named: <GMH, <HMG, or <M.

Triangles  A triangle is a figure with three segments as its sides. Not only does it have three sides, but it has three angles as well. K The figure would be called triangle KLM ( KLM). <K, <L, and <M are all angles within the triangle L M

Union and Intersection  A triangle is the union of three segments. ( )  The intersection of any two sides is a vertex of the triangle. ( ) KL LM = L LM KM= M For example, in the triangle above, KM KL = K KL and LM meet at point L. The point of intersection is L. K L M KL, LM, and KM all join KML, so you would say that KML = KL LM KM.

Practice Problems True or False  1. A point is named with a capital letter.  2. Lines go on forever in one direction.  3. An angle is made up of two segments with a common endpoint.  4. When naming an angle with more than one letter, the vertex letter must be in the middle.  5. A segment is named after its two endpoints.  6. When naming a ray, name the endpoint second.  7. A triangle is the intersection of three points.  8. The intersection of any two sides is a vertex of the triangle.

More Practice Problems 1. Name the coordinate of K. 2. Name all possibilities for the angle. K L Z R 3. Name where OP intersects PT in OPT. 4. Name the ray. O Y W P T

Answers Practice Problems More Practice Problems  1. True 1. The coordinate of K is 4.  2. False 2. <LZR, <Z, or <RZL.  3. False 3. P  4. True 4. YW  5. True  6. False  7. False  8. True

Works Cited Rhoad, Richard, George Miluaskas, and Robert Whipple. Geometry for Enjoyment and Challenge. New Edition ed. Boston: McDougal Littell, Print.

The End