## anonymous 4 years ago 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?

1. anonymous

and how many acres are within the enclosed by the fence?

2. Mertsj

Circumference of the semi-circle is 1/2 pi d or 600 pi or 1885.0 ft. The Area of the semicircle is 1/2 pi r^2 or 1/2 pi (600)^2 or 565486.7 square feet. But one acre is 43,560 sq ft. so 565486.7 sq ft = 13.0 acres

3. anonymous

circumference of the circle is$C=2\pi r$since it's a semi circle, the formula will be$C=\pi r$ given diameter measure is 1200 feet. therefor r=600 substitute to the formula; $C=\pi r$$C=\pi 600$therefor; it is approximately 1884.96 feet