Hello from MrBillDoesMath!
Answer:
3.14
Discussion:
C = circumference, r = radius, d = diameter = 2 r
For a circle, C = 2 Pi r = d Pi
Substituting the values in the question gives
C = d Pi
28.26 = 9 Pi => divide both sides by 9
Pi = 28.26/9 = 3.14
Thank you,
MrB
Hello!

The volume of the square pyramid is approximately 
____________________________________________________________

V = 

First, we must find the area of the square base.
A = l * w
A = 3.5 * 3.5
A = 12.25 km^2
The area of the base is 12.25 km^2. Now, multiply the base area by the perpendicular height. Then divide by 3.
V = (12.25 * 4.7) / 3
V = 19.1916666667
V ≈ 19.19 km^3
The best way to solve this problem is by plugging in each answer choice for both equations and seeing which one works. You can already see that choice A doesn't work because -1 is not greater than or equal to 4. That means you just need to test choices B and C!
Choice B (4, -2)

2 is not greater than or equal to 6, so choice B doesn't work.
Choice C (4, 2)

Since 6 is equal to 6 and 4 is equal to 4, choice C works!
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Answer: C) (4, 2)