1. GEOMETRY HELP Circle A with 3-cm diameter and center C is a dilation of concentric circle B with 8-cm diameter. Describe the dilation. The circles are concentric, so the dilation has center C. Because the diameter of the dilation image is smaller, the dilation is a reduction. The dilation is a reduction with center C and scale factor. 3838 scale factor: diameter of dilation image diameter of preimage 3838 = Quick Check Dilations LESSON 9-5 Additional Examples

2. GEOMETRY HELP The scale factor on a museum’s floor plan is 1 : 200. The length and width on the drawing are 8 in. and 6 in. Find the actual dimensions in feet and inches. Multiply each dimension on the drawing by 200 to find the actual dimensions. Then write the dimensions in feet and inches. 8 in. X 200 = 1600 in. = 133 ft, 4 in. 6 in. X 200 = 1200 in. = 100 ft The museum floor measures 133 ft, 4 in. by 100 ft. The floor plan is a reduction of the actual dimensions by a scale factor of. 1 200 Dilations LESSON 9-5 Additional Examples Quick Check

3. GEOMETRY HELP ABC has vertices A(–2, –3), B(0, 4), and C(6, –12). What are the coordinates of the image of ABC for a dilation with center (0, 0) and scale factor 0.75? The scale factor is 0.75, so use the rule (x, y)  (0.75x, 0.75y). A' is (0.75(–2), 0.75(–3)). B' is (0.75(0), 0.75(4)). C' is (0.75(6), 0.75(–12)). The vertices of the reduction image of ABC are A' (–1.5, –2.25), B' (0, 3), and C' (4.5, –9). Dilations LESSON 9-5 Additional Examples Quick Check