CHAPTER 1: Points, Lines, Planes, and Angles Section 1-2 Points, Lines, and Planes

POINTS Points: Points are represented by dots and actually have no size. We name points with CAPITAL LETTERS. Examples: ● A (Point A)●B (Point B) *All geometric figures consist of points.

LINES Line: Lines extend infinitely in two directions. (We draw arrows on the ends to show this). Lines actually have no thickness.

LINES Lines can be named 2 ways: 1.With one lower case letter: (line m and line l) 2.Using capital letters referring to any 2 points on the line: ● ● AB or BA A B m l

EXAMPLE Name the line 4 different ways: ●●● MNP k

PLANES Plane: A plane is like a piece of paper but does not bend. Unlike paper, planes have no thickness and no edges; planes extend forever. We draw planes like this:

PLANES Planes are often labeled with a capital letter in one “corner”: Plane N N

PLANES A plane can also be named using 3 non- collinear points in the plane. Non-collinear: Not all in a straight line A●●B C● Plane ABC

EXAMPLE Name the plane 3 different ways: X●Y●Z● R● W

EXAMPLES Sketch and label the figures described: 1.Horizontal line m intersects plane X at point R. 2.You try: Vertical line k intersects plane W at point B. 3.A plane Y contains two lines a and b that intersect at point L.

EXAMPLES For the given image (drawn on board): 1.Name one of the planes containing the sides of the pyramid. 2.Name 2 lines that intersect at point Z. 3.Name the line where planes PXY and PZY intersect.

Classwork/Homework CLASSWORK Pg. 7, Classroom Exercises 2-20 even HOMEWORK Pg. 8, Written Exercises 14-26