Lesson Topic: Symmetry in the Coordinate Plane Lesson Objective: I can… Locate reflections of coordinate points across both axes on the coordinate plane using the x-axis and/or y-axis as the line of symmetry. 1:47 Friday It’s important in the real world: finding and comparing locations with more than 2 directions Remind students of behavior goal

Preview of Exit Ticket 1. Start at (-5, 2). Reflect across the x-axis. What point do you end up at? 2. Start at (-5, 2). Reflect across the y-axis. What point do you end up at? Challenge: Come up with a starting point and a set of directions to navigate to an ending point, including at least one reflection. Be sure to include what the ending point is. 1:48

Opening Exercise Give an example of two opposite numbers and describe where the numbers lie on the number line. How are opposite numbers similar and how are they different? 1:50

1:55 When you’re done, Compare with table

2:00 How do you know? What strategies did we use? Compare with table

Exercise, continued… When the coordinates of two points are (𝑥, 𝑦) and (−𝑥, 𝑦), what line of symmetry do the points share? Explain. When the coordinates of two points are (𝑥, 𝑦) and (𝑥,−𝑦), what line of symmetry do the points share? Explain. 2:02 When you’re done, Compare with table

Let’s Sum it Up… Answer the following questions in complete sentences: What does a reflection of a point across a line of symmetry on the coordinate plane look like? How do we find the ordered pair of a point reflected across an axis? Why is this important to know how to do? 2:04 (what are the steps for this process)

Example 2: Navigating the Coordinate Plane using Reflections Where are you after you follow the directions? Begin at (7, 2). Move 3 units down, then reflect over the y-axis. Begin at (4, -5). Reflect over the x-axis, then move 7 units down, then to the right 2 units. Begin at (-3, 0). Reflect over the x-axis then move 6 units to the right. Move up two units, then reflect over the x-axis again. Begin at (-2, 8). Decrease the y-coordinate by 6. Reflect over the y-axis, then move down 3 units. Begin at (5, -1). Reflect over the x-axis, then reflect over the y-axis. *Come up with your own starting points and directions. 2:08 Compare with table

Example 3: Describing How to Navigate the Coordinate Plane Describe a sequence of directions to navigate from the starting point to the ending point. Begin at (9, -3) and end at (-4, -3). Use exactly one reflection across an axis. Begin at (0, 0) and end at (5, -1). Use exactly one reflection across an axis. Begin at (0, 0) and end at (-1, -6). Use exactly two reflections across axes. *Find other sequences that would work for each set of points above. 2:12 Compare with table

Lesson Summary When the coordinates of two points differ only by one sign, such as (-8, 2) and (8, 2), what do the similarities and differences in the coordinates tell us about their relative locations on the plane? What is the relationship between (5, 1) and (5, -1)? Given one point, how can you locate the other? 2:15 opposites “Why is this important to know how to do? / Can anyone think of an example in which it would be important?”: finding and comparing location with more than 2 directions

Evaluate Your Learning 4 3 2 1 How will you “Sharpen Your Saw”? 2:17

Exit Ticket (on Socrative) 1. Start at (-5, 2). Reflect across the x-axis. What point do you end up at? 2. Start at (-5, 2). Reflect across the y-axis. What point do you end up at? Challenge: Come up with a starting point and a set of directions to navigate to an ending point, including at least one reflection. Be sure to include what the ending point is. *When you’re done, close your iPad and get a homework worksheet. 2:22