Warm Up Problem 6.3 x 3.9

Graph on the Coordinate Plane Lesson 5-7

Objectives I can graph a point on the coordinate grid. I can graph a point’s reflection on the coordinate grid.

Example 1 Graph point M at (-3, 5). Each line represents 1 unit. Start at the origin. Move along the x-axis first and then the y-axis.

Example 2 Graph point N at (-2 1 2 , -3 1 2 ). Start at the origin and move along the x-axis and then the y-axis. To plot a 1 2 point, place the point between the lines of the whole numbers.

Got It? Graph and label each point on the coordinate plane. 1) P(-4, 4) 2) Q(0, -4) 3) R(- 1 2 , -2 1 2 ) 4) S(4.5, 1)

Example 3 Graph A(2,-4). Then graph the reflection across the x-axis. Use the notation A’ to label the reflection of A. Remember, to reflect across the x-axis, keep the same x-coordinate and take the opposite of the y-coordinate. So, A’ is (2, 4).

Example 4 Graph B(-1.5, 3). Then graph its reflection across the y-axis. Remember, to reflect across the y-axis, keep the same y-coordinate and take the opposite of the x-coordinate. So, B’ is (1.5, 3)

Got It? 5) Graph C(-1,-5). Then graph its reflection across the x-axis. 6) Graph D(2, 3 1 2 ). Then graph its reflection across the y-axis.

Example 5 Mr. Martin is using a coordinate plane to design a logo. He graphs points at (2,4) and (2, -2). He reflects (2, -2) across the y-axis. Then he reflects the new point across the x-axis. What figure is Mr. Martin using for his new logo? Mr. Martin is making a trapezoid.

Got it? 7) Ms. Shaull is drawing a map of school. Her room is at (-3, 4) and the gym is (3, 4). The library is the reflection of (3, 4) across the x-axis. This point is then reflected across the y-axis to graph the office. What is the shape of the figure on the map?

Homework Hint #18 Step 1: Choose any point in the 1st quadrant. Step 2: Reflect this point over the y-axis…did the x-coordinate become negative? Step 3: Now chose any point in 2nd quadrant. Step 4: Reflect this point over the y-axis…did the x-coordinate become negative? If your answers are yes, and then no, then your final answer is “sometimes”. You can use a graph to help explain.