4.A: Reflections and Translations
- Page ID
- 31455
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Overview
The purpose of this lesson is to learn how to represent reflections and translations on the coordinate plane.
This lesson will address the following CCRS Standard(s) for Geometry:
- 8.G.2: Understand that a two-dimensional figure is congruent to another if the second can be obtained from the first by a sequence of rotations, reflections, and translations; given two congruent figures, describe a sequence that exhibits the congruence between them
Directions
- Take notes while watching videos below
- Go to http://wamap.org and log into our course to complete assignment 4.A with 80% or better.
Do
Complete assignment 4.A with 80% or better at http://wamap.org
Summary
In this lesson we have learned:
- Reflections create a mirror image of the original shape which is congruent to the original shape
- Reflecting (a,b) over the x-axis gives the point (a,-b)
- Reflecting (a,b) over the y-axis gives the point (-a,b)
- Reflecting (a,b) over the origin gives the point (-a,-b)
- Reflecting (a,b) over the line y=x gives the point (b,a)
- Translations slide the original shape creating a second congruent shape
- Translating (a,b) up c and right d units gives (a+d,b+c)