Divide $55.65 by 7 to get the cost of 1 key chain ($7.95). Then multiply the cost of 1 by 12 and get $95.40
Circular pen means you are going to use Area = Pi(r^2).
So 78.5 = pi(r^2). Divide by pi on both sides to get r^2 = 78.5/pi. Take the square root of that to get r or radius = approximately 4.99. If you need an exact answer then use
for the next part because you are not done yet.
Plug whatever R you use into the circumference formula of Circumference = 2(pi)(r).
If you use 4.99, you do 2(pi)(4.99) which is approximately 31.35. If you use the exact answer, you do 2(pi)(
) which gives you approximately 31.41.
Either way you'll need about 31 meters of chicken wire but the 31.40796 or ~31.41 is closer to the exact answer.
18 line segments also for faster and better u can 6 times 3 since there is already three in a triangle.