math smarties=]?

Question

heres the info
-mr.klinger and his son own a cattle farm. they have been losing cattle in the swamp, the forest and the river that border their land. they want to build a fence to emclose their farm. they know that the fence will form a semicircle. two sides of a rectangle and the hypotenuse of a triangle.

-the triangle is 300ft
-the square is 600ft and 400ft
-the semicircle is 900ft

part a-how many feet of fencing will they have to buy? please explain

Answer 1

It's always much easier if there is a diagram, so I drew one:
http://img391.imageshack.us/img391/1975/fenceje8.gif

Starting with the semi-circle, you need the formula for a circumference. The diameter is 900 ft.

C = πd
C = 900π
C ≈ 2,826 ft.

But you have a semi-circle, so it is half of this:
½C = ½(900π)
½C = 450π
½C ≈ 1,413 ft.

The two sides of the rectangle are obvious. They are 600 ft. and 400 ft. respectively.

Finally you have the right triangle. The two legs are 300 and 400 ft. Using the Pythagorean Theorem:
300² + 400² = c²
90000 + 160000 = c²
250000 = c²
c = √250000
c = 500 ft.

Adding it all up:
1413 + 400 + 600 + 500
= 1913 ft. of fencing.