# math

posted by on .

Mr. Fairchild wants to add a playroom and a bedroom to his house. The 2rooms will be proportional, but the bedroom's dimensions will be only 1/3 as large as the playroom.
If the playroom of the bedrooom is 50 ft. then the perimeterof the playroom will be what?
i think i have to do p= 2w+2l, then put 20=2*l+2W, but how do i get the legth and width if the shape is a rectangle

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If the dimensions are 1/3 the original, then the perimeter of the bedroom will be 1/3 the perimeter of the playroom.

Not asked, but the area of the smaller room will be 1/9 the area of the larger room.

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thank you bobpursley

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You have a typo up there.
If the playroom of the bedroom ???

If you mean the perimeter of the bedroom is 50 feet.
then the perimeter of the playroom will be 50*3 = 150 feet

Unlike volume or area, linear dimensions scale all with the scale ratio which is 3 here.

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im sorry for the typo, i meant to type the perimeter of the bedroom

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Now for example if the bedroom were 15 feet long and 10 feet wide
P = 30 + 20 = 50 feet
then
playroom = 45 long and 30 wide
P = 90 + 60 = 150 feet

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oh. i get it. so since the question soesn't say the length or the width, you don't really need them. you just need the perimeter, and the fraction to multiply by. right? i thik i get it. sort of

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oh. i feel really dumb now. sorry for the typo i have another question just like that one, but instead, it has different sizes. so i just mult. the perimeter and three. that seems pretty simple. thank you.
again.

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If all the dimensions are three times, then the perimeter is three times.
Watch out if they ask for the area though. That would be 9 times as Bob Pursley said. 3^2 = 9

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oh, so if its area, then you have to square the #, just like Bob Pursley said 3^2=9
but if its perimeter, i have to multiply the perimeter by, say the dimensions are 5. then i'd have to multiply the perimeter by 5. i think i get it.
THANk YOU.
(again)

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You have the idea now I think. You are very welcome.