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.
It would cost $896 to plate fencing around the garden
2(3t - 1) - 5(t - 1)
2(3t) - 2(1) - 5(t) + 5(1)
6t - 2 - 5t + 5
6t - 5t - 2 + 5
t + 3
Step-by-step explanation:
Equation of given line is:

Thus, the slope of required line is 2.
For 1 hour, money = $20
For $140, it would be: 140/20 = 7 hours.
So, option C is your final answer.
Hope this helps!