math
posted by brianna 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

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. 
thank you bobpursley

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

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 
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

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