Essential Understanding You can use ratios to compare the perimeters and areas of similar figures Students will be able to find the perimeters and areas of similar figures

Perimeters and Areas of Similar Figures If the scale factor of two similar figures is a/b, then The ratio of their perimeters is a/b The ratio of their areas is a 2/b 2

Finding Ratios Two similar polygons have corresponding sides in the ratio 5: 7 What is the ratio (larger to smaller) of their perimeters? What is the ratio (larger to smaller) of their areas?

Finding Area The scale factor of two similar parallelograms is ¾. The area of the larger parallelogram is 96 in 2. What is the area of the smaller parallelogram?

Finding Area The area of the smaller regular hexagon is about 127. 3 ft 2. What is the best approximation for the area of the larger regular hexagon?

Applying Area The scale factor of the dimensions of two similar pieces of window glass is 3: 5. The smaller piece costs $2. 50. How much should the larger piece cost?

Applying Area

Finding Perimeter The areas of two similar rectangles are 1875 ft 2 and 135 ft 2. What is the ratio of their perimeters?