Aim What is a reflection and how do they impact geometric figures? Announcement Homework Practice 92 #19 Do Now Please take a polygon (no circles), and a couple pieces of patty paper from the back of the room. Classwork Reflections are flips. Geometric figures flip over the line of reflection. Students noticed that during a reflection, the orientation of the vertices changes. They also noticed that preimage points and their corresponding images are equidistant to the line of reflection. From yesterday  Today we began a unit on transformations. A transformation is a change in position, shape, or size for a geometric figure. The transformation we learned about today is a translation, which is a slide. On a coordinate plane, a translation lifts a figure and moves it, leftright, updown. Adding to xvalues moves to the right, subtracting xvalues moves the figure to the left. Adding to the yvalues moves the figure up, subtracting to the yvalues moves the figure down. So the notation (x  3, y + 4) means the figure moves three units to the left and then 4 units up. The original figure is called a preimage while the figure after the transformation is called the image. We also learned that some transformations preserve congruency, meaning the the preimage and image are congruent to each other. Transformations that preserve congruency are called an isometry. Resources
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AuthorMr. Severiano Archives
June 2018

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