# Area/Perimeter Function Problem

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• Sep 30th 2009, 06:46 PM
kittykat616
Area/Perimeter Function Problem
I posted a problem last week with this same picture and got some great help- many thanks ahead of time!
http://i13.photobucket.com/albums/a2.../mathprblm.jpg
Find the perimeter function in terms of x if the area function is A(x)= 28 sq. ft.
• Sep 30th 2009, 07:12 PM
Arturo_026
So, i guess your area is
P(x) = pi*x + 2y + 2x

now substitute A(x) for 28
and get your answer in terms of x

I hope I'm right.
• Sep 30th 2009, 07:28 PM
kittykat616
Would the area be 2xy + 1/2pi * (x)^2??
• Sep 30th 2009, 07:30 PM
Arturo_026
Quote:

Originally Posted by kittykat616
Would the area be 2xy + 1/2pi * (x)^2??

Yes, considering that the radius os the semicircle is x
• Sep 30th 2009, 07:34 PM
kittykat616
Alright. So would the peimeter be (2x+2y)+ Pi (x)? Then put the area function every where there is x??
• Sep 30th 2009, 07:41 PM
Arturo_026
I misunderstood your question in the first post, sorry.

Yes, with the perimeter function find the value of y in terms of x and then substitute that in the area function.
• Sep 30th 2009, 07:47 PM
kittykat616
So, the value of y in terms of x would be

x=2y + 1/2pi(x) , right?

Sorry for so many questions!