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Geometry 1-7 Day 1. Transformations in the Coordinate Plane. Learning Targets. Students will be able… Identify reflections, rotations, and translations. Graph transformations in the coordinate plane. Warm-up. 1. Find the circumference and area of a circle with radius 5.
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Geometry 1-7 Day 1 Transformations in the Coordinate Plane
Learning Targets • Students will be able… • Identify reflections, rotations, and translations. • Graph transformations in the coordinate plane.
Warm-up 1. Find the circumference and area of a circle with radius 5. 2. Find the distance between point J and point T. J(7, 1) and T(-2, -4)
Vocabulary • Transformation • A change in position, size, or shape of a figure. Does anyone know of a type of transformation?
Reflection Construction • Fold your paper in half. Draw the line that is formed by the fold. • Label the fold “Line of Reflection” • Draw a triangle on one side of your paper. Label the vertices. • Place your Mira on the fold of your paper. • Look through the Mira to draw it’s reflection. Label the vertices as you see them in the Mira. * You have now constructed a Reflection. We will look at the characteristics that are present!
Reflection Construction • Draw a line from A to A’. • Find the measure from A to the line of reflection. • Find the measure from A’ to the line of reflection. What do you notice? Equal Distance! You could continue this for B to B’ and C to C’
Reflection Construction • What do you notice between your line drawn from A to A’ and the Line of Reflection? • Perpendicular • Now lets write the identification. Reflection,
Rotation Construction • Draw a rectangle or a triangle. (Go over it with a marker so you can really see it) • Label a point P outside of your figure. • This is your point of reflection • Take another sheet of paper and place it over the top of the figure. TRACE EVERYTHING (the figure and the point of reflection) • Place the copied figure underneath the original. Line up all points.
Rotation Construction 5. Rotate the figure underneath the original. Make sure that point P is still lined up. 6. Redraw this figure labeling the new points with apostrophes. 7. Measure the distance from… C to P and C’ to P B to P and B’ to P A to P and A’ to P What do you notice?
Rotations • When you can identify a specific degree of turn for a rotation you should write it. • For example rotation 90°, 180°, 270°
More Vocabulary • Preimage • The original figure. • Image • The figure after it is reflected, rotated or translated. • Has the apostrophes
Examples • Preimage • Image B B’ A C’ C A’
Notation Steps • Write the type of transformation. • Label the preimagefigure. • Write an arrow. • Label the image (label the same points in the same order just use an apostrophe ‘ ).
Example 1: Identify each transformation. Then use arrow notation to describe the transformation.
Example 1: Identify each transformation. Then use arrow notation to describe the transformation.
Example 1: Identify each transformation. Then use arrow notation to describe the transformation.
Example 1: Identify each transformation. Then use arrow notation to describe the transformation.
Example 2: Graph Paper Needed 1. A figure has vertices at A(-1, 4), B(-1, 1), and C(3, 1). After a transformation, the image of the figure has vertices at A’(-1, -4), B’(-1, -1), and C’(3, -1). Draw the preimage and image. Then identify the transformation. Reflection across the x-axis.
Example 2: Graph Paper Needed 1. A figure has vertices at E(2, 0), F(2, -1), G(5, -1) and H(5, 0). After a transformation, the image of the figure has vertices at E’(0, 2), F’(1, 2), G’(1, 5) and H’(0, 5). Draw the preimage and image. Then identify the transformation. Rotation, 90°
Wrap-up • Without looking back at your notes who can tell me all three types of transformations?