Geometry question, i appreciate any !

A]
Volume ratio is given by:
(volume of large sphere)/(volume of small sphere)
volume of large sphere=686 yd³
volume of small sphere=250 yd³
thus
volume ratio will be:
686/250
=343/125

b] Linear scale factor=∛(volume ratio)
but
volume ratio=343/125
hence:
scale factor=∛(343/125)=∛(7³/5³)=7/5

c] area ratio=(scale factor)²
but
scale factor=7/5
thus
area ratio=(7/5)²=49/25

820,000 is the answr