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?

Question

anonymous · Answer

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

mertsj · Answer

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

anonymous · Answer

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