Notes 21 The Coordinate Plane 5-1

Vocabulary Coordinate plane- a plane containing a horizontal number line and a vertical number line. X-axis- the horizontal number line on a coordinate plane. Y-axis- the vertical number line on a coordinate plane. Origin- the intersection of the x-axis and y-axis. Quadrant- the four regions of the coordinate plane, which are numbered I,II,III,IV. Ordered pair- consists of two numbers in a certain order.

x y A coordinate plane is a plane containing a horizontal number line, the x-axis, and a vertical number line, the y-axis. The intersection of these axes is called the origin. 5 y-axis 4 Quadrant II 3 Quadrant I 2 x-axis 1 –5 –4 –3 –2 –1 Origin 1 2 3 4 5 –1 –2 Quadrant III –3 Quadrant IV –4 –5 The axes divide the coordinate-plane into four regions called quadrants, which are numbered I, II, III, and IV.

Additional Example 1: Identifying Quadrants on a Coordinate Plane Identify the quadrant that contains each point. x y –2 2 –4 4 –1 –3 –5 5 3 1 A. S W S lies in quadrant IV. T B. T T lies in quadrant I. C. W S W lies on the y-axis between Quadrants I and II

On your own. Highlight the answer. Check It Out: Example 1 On your own. Highlight the answer. Identify the quadrant that contains each point. x y –2 2 –4 4 –1 –3 –5 5 3 1 A. N N B. X Y C. Y X

x y –2 2 –4 4 –1 –3 –5 5 3 1 Points on a coordinate plane are identified by ordered pairs. An ordered pair consists of two numbers in a certain order. The origin is the point (0,0). 2 units up 3 units right Ordered pair (3, 2)‏ x-coordinate y-coordinate Units right or left from 0 Units up or down from 0

Additional Example 2: Plotting Points on a Coordinate Plane Plot each point on a coordinate plane. x y –2 2 –4 4 –1 –3 –5 5 3 1 A. D (3, 3)‏ D Start at the origin. Move 3 units right and 3 units up. B. E (–2, –3)‏ Start at the origin. Move 2 units left and 3 units down. E F C. F (3, –5)‏ Start at the origin. Move 3 units right and 5 units down.

On your own. Highlight the answer. Check It Out: Example 2 On your own. Highlight the answer. Plot each point on a coordinate plane. x y –2 2 –4 4 –1 –3 –5 5 3 1 A. D (4, 4)‏ B. E (–2, 3)‏ C. F (–1, –2)‏

Additional Example 3: Identifying Points on a Coordinate Plane Give the coordinates of each point. x y –2 2 –4 4 –1 –3 –5 5 3 1 A. X (–2, 5)‏ X Start at the origin. Point X is 2 units left and 5 units up. Y B. Y (–1, 0)‏ Start at the origin. Point Y is one unit left on the x-axis. Z C. Z (3, –3)‏ Start at the origin. Point Z is 3 units right and 3 units down.

On your own. Highlight the answer. Check It Out: Example 3 On your own. Highlight the answer. Give the coordinates of each point. x y –2 2 –4 4 –1 –3 –5 5 3 1 A. L N L B. M M C. N