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.
Answer:
9 degrees
Step-by-step explanation:
The temperatire was -3 and then rose by 12, -3 + 12 = 9
(60 / - 20 ) x 100% = 300%
Answer:
d = 4 units
Step-by-step explanation:
The diameter is twice the radius
d = 2r
d = 2(2)
d = 4 units