How do i solve this? i don't understand how i would even start this problem to solve it

Step-by-step explanation:

To start the problem, you recognize that the figure is a cone with a radius of 21 ft and a height if 12 ft.

Then, you consult your list of volume formulas to find the one for the volume of a cone. It is ...

  V = (1/3)πr²h . . . . . where r is the radius and h is the height

Fill in the given numbers and do the arithmetic.

  V = (1/3)π(21 ft)²(12 ft) = 1764π ft³ ≈ 5542 ft³

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If your calculator does not have a button for π, you can use 3.14159. Most spreadsheets will have a PI() function that will give this value.