Answer:
70 ft
Step-by-step explanation:
You want the perimeter of a patio 20 ft long that is similar in shape to a yard that is 60 ft long and 45 ft wide.
The ratio of patio length to yard length is ...
(20 ft)/(60 ft) = 1/3
The perimeter of the yard is ...
P = 2(L+W)
P = 2(60 ft +45 ft) = 210 ft
The perimeter of the patio is this length, multiplied by the scale factor:
patio perimeter = (210 ft)(1/3) = 70 ft
The perimeter of the new patio is 70 ft.
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Additional comment
Alternatively, you can recognize the width is 3/4 of the length, so the width of the patio is 15 ft. Then the perimeter formula gives you ...
p = 2(20 ft +15 ft) = 70 ft
