1. Transformations: Dilations
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2. Dilations
Tell me what you already know!
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3. Dilations
Dilations video clip
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4. Dilations: Lesson Objectives
You will be able to:
Describe a dilation;
Find the coordinates of a dilated polygon;
Graph a polygon and its dilation; and
Describe the change in area of a dilated polygon.
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5. Dilations
A dilation is a transformation that changes the size but the shape of
an object.
Every dilation has a fixed point that is called the center of dilation.
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6. Dilations To dilate an polygon: Graph the polygon.
Multiply the x and y coordinates of
each of the polygon’s vertices by the given scale factor.
Graph the new points.
Connect the points to form the dilated polygon.
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7. Dilations
Example 1:
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8. Dilations Multiply each point’s coordinates by 2:
Example 1:
Multiply each point’s coordinates by 2:
A = (1 x 2, 1 x 2)  A’ = (2, 2)
B = (1 x 2, 3 x 2)  B’ = (2, 6)
C = (3 x 2, 1 x 2)  C’ = (6, 2)
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9. Dilations
Example 1:
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10. Dilations
Example 1:
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11. Dilations
Your turn:
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12. Dilations
Your turn:
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13. Dilations Sunshine State Standards:
C.1.3.1: The student understands the basic properties of, and relationships pertaining to two-dimensional regular and irregular geometric shapes.
C.2.3.1: The student understands the geometric concepts of symmetry, reflections, congruency, similarity, perpendicularity, parallelism, and transformations, including flips, slides, turns, and enlargements.
B.1.3.3: The student understands and describes how the change of a figure in such dimensions as length, width, height or radius affects its other measurements such as perimeter, area, surface area, and volume.
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14. Dilations GeoGebra dynamic worksheets: Dilation of a square
Dilation of a circle
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