A rectangle has a length of 4 feet and a perimeter of 14 feet. what is the perimeter of a similar rectangle with a width of 9 feet?a. 36 ftb. 108 ftc. 42 ftd. 126 ft
Question
Answer:
First Rectangle: P= 14; L= 4, W= ?Second Rectangle: P= ?, L= ?, W= 9
STEP 1:
solve for the width in the first rectangle using perimeter formula
Perimeter= 2L + 2W
14= 2(4) + 2W
14= 8 + 2W
subtract 8 from both sides
6= 2W
divide both sides by 2
3= W
STEP 2:
Since the two rectangles are similar, they may be different sizes, but they have corresponding angles. We can set up a ratio to compare width and length.
First Rectangle: P= 14, L= 4, W= 3
Second Rectangle: L= ?, W= 9
length/width= length/width
4/3= L/9
cross multiply
4 * 9= 3 * L
36= 3L
divide both sides by 3
12= L
STEP 3:
find perimeter of second rectangle; use length from step 2
Perimeter= 2L + 2W
=2(12) + 2(9)
=24 + 18
=42 feet
ANSWER: (C) 42 feet
Hope this helps! :)
solved
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10 months ago
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