Essential UnderstandingEssential 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 RatiosFinding 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 AreaFinding 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 AreaFinding Area  The area of the smaller regular hexagon is about ft 2. What is the best approximation for the area of the larger regular hexagon?

Applying AreaApplying 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 AreaApplying Area

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

Perimeter

Homework  Pg. 638  # 9 – 18, 20 – 28 even, 46  16 problems