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:
198
Step-by-step explanation:
If you take any 3-digit number and change the numbers around and subtract them you will always get 198.
Answer:
They are taking 12 2 credit courses
The are taking 4 1 credit courses
Step-by-step explanation:
x = 1 credit courses
y = 2 credit courses
The number of courses is 16
x+y = 16
The number of credits is 28 so multiply the course by the number of credits
1x+2y=28
Subtract the first equation from the second equation
x+2y =28
-x-y=-16
-----------------
y = 12
They are taking 12 2 credit courses
We still need to find the 1 credit courses
x+y = 16
x+12= 16
Subtract 12 from each side
x-12-12 = 16-12
x =4
The are taking 4 1 credit courses
3.45. All you have to do is divide 10.35 by 3.