Whit what part? Sorry i cant help
Formula = 4/3 x pi x r^3
4/3 x 3.14 x 7^3 = 1436.03
answer: a. 1436.03 cubic units
Suprisingly the answer is $280,000. This is answer because when you round 35.50 it is 40. When you round 6,789 it is 7,000. 40 times 7,000 is 280,000
~JZ
Answer
Find out the what fraction of the sandcastle did they build together .
To prove
Let us assume that the fraction of the sandcastle they build together be x .
As given


Than the equation becomes

L.C .M of (3,7) = 21
solving


Therefore the fraction of the sandcastle did they build together be

Hence proved