~, you~
( show a simple and easy way of solving this problem, you ^_^)

Volume=pi*(radius^2)*(height of cone/3) so in this case Volume= pi*6^2*(12/3). Simplify pi*36*4. Simplify again and you get Volume=452.16 cubic meters.

The volume of  a pyramid with hight and base is 1/3 the volume of a rectangleular prisim with the same height and base

also the volume of  a cone is 1/3 the volume of a cylinder with same height and base so
just fun facts to know (helpful)

so volume of cylinder=1/3 times height tiimes pi times radius^2
subsitute
use pi=3.14
height=12
radius=6
volume=1/3 times 12 times 3.14 times 6^2
volume=4 times 3.14 times 36
volume=452.16 cubic meters
the naswer is the top left choice

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.