SOLUTION: 1)Perimeter. Write a formula for the perimeter of a square as a function of its area and 2) Area of a sign. A sign is in the shape of a squ

Algebra ->  Equations -> SOLUTION: 1)Perimeter. Write a formula for the perimeter of a square as a function of its area and 2) Area of a sign. A sign is in the shape of a squ      Log On


   



Question 184037: 1)Perimeter.
Write a formula for the perimeter of a square as a function of its area
and
2)
Area of a sign.
A sign is in the shape of a square with a semicircle of radius x adjoining one side and a semicircle of diameter x removed from the opposite side. If the sides of the square are length 2x, then write the area of the sign as a function of x.

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Write a formula for the perimeter of a square as a function of its area:
:
we know the area of a square = side squared
Therefore, one side = square root of the area (a)
Perimeter (P) is the sum of all 4 sides:
so we have:
:
P(a) = 4%2Asqrt%28a%29
:
:
and
2)
Area of a sign.
A sign is in the shape of a square with a semicircle of radius x adjoining one side and a semicircle of diameter x removed from the opposite side. If the sides of the square are length 2x, then write the area of the sign as a function of x.
:
Write an expression for the area of each part:
:
Attached semi circle: %28pi%2Ax%5E2%29%2F2; (radius=x)
;
the square: %282x%29%5E2; (side=2x)
:
removed semi circle: %28pi%2A%28.5x%29%5E2%29%2F2; (radius=.5x)
:
f(x) = area of the sign
Total area = large semi circle + square - small semicircle
:
f(x) = %28pi%2Ax%5E2%29%2F2 + %282x%29%5E2 - %28pi%2A%28.5x%29%5E2%29%2F2
f(x) = %28pi%2Ax%5E2%29%2F2 + %284x%5E2%29 - %28pi%2A%28.25x%5E2%29%29%2F2
get each expression over 2
f(x) = %28pi%2Ax%5E2%29%2F2 + %288x%5E2%29%2F2%29 - %28pi%2A%28.25x%5E2%29%29%2F2
so we have
f(x) = %28pi%2Ax%5E2+%2B+8x%5E2+-+pi%2A.25x%5E2%29%2F2
Factor out x^2
f(x) = %28x%5E2%28pi+%2B+8+-+.25pi%29%29%2F2
combine the pi's
f(x) = %28x%5E2%28.75pi+%2B+8%29%29%2F2