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Learn how to draw reflections in the coordinate plane. Understand the concept of reflection and its properties. Practice graphing reflected images.
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I can draw reflections in the coordinate plane. 9.1: Reflections Agenda: 9.1 Notes
If the images to the right describe a reflection, in your own words, define reflection:
Vocabulary! A line in which each point on the preimage and its corresponding point on the image are the same distance from the line. • If a point is on the line of reflection, then • image and preimage are the same point • If a point is not on the line of reflection, • then the line of reflection is the perpendicular • bisector of the line joining corresponding points • in the image and preimage.
Example 1: Draw the reflected image of quadrilateral WXYZ in line p.
Add to Notes! X = # (A NUMBER) IS A VERTICAL LINE Y = # (A NUMBER) IS A HORIZONTAL LINE
Example 2: Quadrilateral JKLM has vertices J(2, 3), K(3, 2), L(2, –1), and M(0, 1). a) Graph JKLM and its image over x = 1.
Example 2: Quadrilateral JKLM has vertices J(2, 3), K(3, 2), L(2, –1), and M(0, 1). b) Graph JKLM and its image over y = –2 .
Example 3: Quadrilateral ABCD has vertices A(1, 1), B(3, 2), C(4, –1), and D(2, –3). a) Graph the image reflected in the x – axis.
Example 3: Quadrilateral ABCD has vertices A(1, 1), B(3, 2), C(4, –1), and D(2, –3). b) Graph the image reflected in the y – axis.
Brain Break! • You may stand or remain seated for this activity. • Move your right foot in a clockwise circle, • Simultaneously, with your right pointer finger, write the number 6 in the air. • Repeat this pattern several times and then switch to the other foot and hand. • Try reversing the motions to counter-clockwise and the number 9.
Reflection in the line *interchange x and y
Example 4: Quadrilateral ABCD has vertices A(1, 1), B(3, 2), C(4, –1), and D(2, –3). Graph the image under reflection of the line y = x.
You Try! 1. Graph the image of the figure below using the transformation given. a) Reflection across the x-axis
You Try! 1. Graph the image of the figure below using the transformation given. b)reflection across y = 3
You Try! 2. Given the coordinate points of an image, graph the points below. Then use the transformation given to plot the new figure. c)reflection across the x-axis T(2, 2), C(2, 5), Z(5, 4), F(5, 0)
You Try! 2. Given the coordinate points of an image, graph the points below. Then use the transformation given to plot the new figure. d)reflection across y = −2 H(−1, −5), M(−1, −4), B(1, −2), C(3, −3)
Homework: 9.1 Worksheet