4.5 Dilations

Similarity, Right Triangles, and Trigonometry G G-SRT:
Understand similarity in terms of similarity transformations.
1. Verify experimentally the properties of dilations given by a center and a scale factor:
a.  A dilation takes a line not passing through the center of the dilation to a parallel line, and leaves a line passing through the center unchanged.
b. The dilation of a line segment is longer or shorter in the ratio given by the scale factor.
2.Given two figures, use the definition of similarity in terms of similarity transformations to decide if they are similar; explain using similarity transformations the meaning of similarity for triangles as the equality of all corresponding pairs of angles and the proportionality of all corresponding pairs of sides.
Geometric Measurement and Dimension G-GMD  
Visualize relationships between two-dimensional and three-dimensional objects.
5.  Know that the effect of a scale factor k greater than zero on length, area, and volume is to multiply each by k, k2, and k3, respectively; determine length, area and volume measures using scale factors. CA 

Khan Practices:

Dilations: Scale Factor