Question

A rectangle has width of 4 feet. Find a function that models it's area A in terms of Its perimeter P.

Answer 1

Start with what you know about the perimeter

P = 2(4) + 2l

or

P = 2l + 8


so make l the subject.

now for Area

Area = l * w

you know w = 4

so using what you know

Area = 4l

now substitute the value of l from the perimeter

for the final answer

Answer 2

Where do I plug that in ?

Answer 3

\[Area =4 \times l\]

and the perimeter is

\[P = 8 + 2l\]

can you make l the subject... in the perimeter equation

Answer 4

The answer is suppose to be A(P) = 2P-16 ??

Answer 5

yep... we'll get to that...

in the perimeter equation above can you make length (l) the subject...