Dale Copy of 8.GM.1 - Messing With Lisa Reflections Only

Author:: Dan Dale, Tim Brzezinski, Sharon Mahon

Topic:: Dilation, Reflection, Rotation, Geometric Transformations, Translation

Let's Reflect Mona!

A reflection is a transformation that is called a flip. Reflections make mirror images and creates a line of symmetry.

To work this applet...

Make sure to click on the box next to Reflect Mona About Line. We want to reflect Mona across the x-axis, so we will drag the yellow line so that both yellow points are on the x-axis.

Note: LARGE POINTS are MOVEABLE.

Make Mona reflect across the x-axis. The x-axis will be the line of symmetry. If a point is 4 beneath the x-axis before the flip, then it will be 4 above the x-axis after the flip.

1) Where is the point (2,-4) after a reflection across the x-axis? 2) Where is the point (5,-4) after a reflection across the x-axis? Answer below.

Make Mona reflect across the y-axis. You will need to drag the yellow line so that the two yellow points are on the y-axis.

1) Where is the point (2,-4) after a reflection across the y-axis? 2) Where is the point (5,-4) after a reflection across the y-axis? Answer below.

Hopefully you noticed a shortcut with reflections. If you reflect across the x-axis, your x-values of each point stays the same and your y-values will all be opposite from the initial points. If you reflect across the y-axis, your y-values stay the same a

Where would the new points be if A(2,4) B(4,1) C(-3,5) after a reflection across the x-axis? Answer below. Use A', B', and C' to indicate the new points.

Question 1:

Question 2

Question 3

Question 1 Answer _________ Question 2 Answer _________ Question 3 Answer _________ Answer below.