8th grade Ch 7 L7

For each pair of similar figures, find the perimeter of the second figure. The first hexagon has a perimeter of 18 cm and each side is 3 cm. The second hexagon has each side 4 cm. What is the perimeter (P) of the second hexagon?

• 24 cm

• 20 cm

• 28 cm

• 18 cm

For each pair of similar figures, find the perimeter of the second figure. The first parallelogram has a perimeter of 21 ft and a side of 5 ft. The second parallelogram has a side of 2 ft. What is the perimeter (P) of the second parallelogram?

• 8.4 ft

• 6 ft

• 10.5 ft

• 12 ft

Julie is enlarging a digital photograph on her computer. The original photograph is 5 inches by 7 inches. If she enlarges the dimensions 1.5 times, what will be the perimeter and area of the new image?

• Perimeter: 36 inches, Area: 78.75 square inches

• Perimeter: 30 inches, Area: 52.5 square inches

• Perimeter: 28 inches, Area: 49 square inches

• Perimeter: 32 inches, Area: 70 square inches

If you know two figures are similar and you are given the area of both figures, how can you determine the scale factor of the similarity?

• Take the square root of the ratio of their areas.

• Divide the area of one by the perimeter of the other.

• Multiply the areas together and take the square root.

• Subtract the smaller area from the larger area.

For each pair of similar figures, find the perimeter of the second figure. Given: First triangle has a perimeter of 38 mm. Second triangle has a side of 18 mm. What is the perimeter (P) of the second triangle?

• 57 mm

• 36 mm

• 42 mm

• 76 mm

The city of Brice is planning to build a skate park. An architect designed the area shown at the right. In the plan, the perimeter of the park is 80 inches. If the actual length of WX is 50 feet, what will be the perimeter of the actual skate park?

• 160 ft

• 80 ft

• 100 ft

• 200 ft

A child’s desk is made so that the dimensions are two-thirds the dimensions of a full-size adult desk. Suppose the top of the full-size desk measures 54 inches long by 36 inches wide. What is the perimeter and area of the top of the child’s desk?

• Perimeter: 120 in.; Area: 864 sq in.

• Perimeter: 80 in.; Area: 648 sq in.

• Perimeter: 60 in.; Area: 432 sq in.

• Perimeter: 72 in.; Area: 324 sq in.

Theo is constructing a miniature putting green in his backyard. He wants it to be similar to a putting green at the local golf course, but one third the dimensions. The area of the putting green at the golf course is 1,134 square feet. What will be the area of the putting green Theo constructs?

• 126 sq ft

• 378 sq ft

• 378 sq ft

• 378 sq ft

Craig is making a model version of his neighborhood that uses model trains. The ratio of the model train to the actual train is 1:64. His neighborhood covers an area of 200,704 square feet. What will be the area of the model neighborhood?

• 49 sq ft

• 64 sq ft

• 128 sq ft

• 32 sq ft

Persevere with Problems: Two circles have circumferences of π and 3π. What is the ratio of the area of the circles? the diameters? the radii?

• 1:9, 1:3, 1:3

• 1:3, 1:9, 1:3

• 1:3, 1:3, 1:9

• 1:9, 1:3, 1:9