Answer:
(The image is not provided, so i draw an idea of how i supposed that the problem is, the image is at the bottom)
Ok, we have a rectangle of length x by r.
At the extremes of length r, we add two semicircles.
So the perimeter will be equal to:
Two times x, plus the perimeter of the two semicircles (that can be thought as only one circle).
The radius of the semicircles is r, and the perimeter of a circle is:
C = 2*pi*r
where pi = 3.14
Then the perimeter of the track is:
P = 2*x + 2*pi*r.
b) now we want to solve this for x, this means isolating x in one side of the equation.
P - 2*pi*r = 2*x
P/2 - pi*r = x.
c) now we have:
P = 660ft
r = 50ft
then we can replace the values and find x.
x = 660ft/2 - 3.14*50ft = 173ft
