Answer:
1386cm^2.
Step-by-step explanation:
radius of circle=21cm
area of circle(a)=?
we know,
A=pi r^2
=22/7×(21)^2
=1386cm^2
1250 lbs of sand.
So first let's find the volume of the sand in the sandbox. You have a square sandbox, with a side length of 5, meaning you have a length and width of 5. You also have half a foot of sand in the sandbox, meaning that you have a height of 0.5. To find the volume of the sand, multiply the length by the width by the height:

So you have 12.5 cubic feet of sand. If each cubic foot of sand is 100 lbs, then you just multiply the two:
This is easy once you look at it you just have to move the decimal 7 places and you'll get 24,000,000