Question

A contractor has installed a silt fence around an area that is semi-circular and level to prevent soil from the construction site entering nearby streams. The diameter of the semi-circle is 1200 feet. How many linear feet of fence does the contractor need to use to enclose the area?

Answer 1

3085
[(1200xpí)/2]+1200

Answer 2

The answer is
`(600\pi+1,200)\ ft` or
`3,085\ ft`

Explanation:

we know that

The circumference of a circle is equal to

`C=\pi D`

where

D is the diameter of the circle

In this problem, to calculate how many linear feet are needed, find the perimeter of a semicircle

so

`(\pi D)/(2)+D`

we have

`D=1,200\ ft`

substitute the value

`(\pi (1,200))/(2)+1,200=(600\pi+1,200)\ ft`

`(600\pi+1,200)\ ft=3,085\ ft`