To determine the amount of gold plating necessary for the similar box, you will use the fact that it is 8 times larger in volume to determine how many times larger the area is. This would be what you will multiply $125 by.
Volume is a three dimensional measurement, so the fact that it is 8 times larger tells us each dimension was 2 times larger (2 x 2 x 2=8).
Area is a two dimensional measurement, so the area would have been 2 x 2 or 4 times larger. This means the price would be 4 times as much. $125 x 4 = $500.
It will cost $500 to gold plate the similar jewelry box.
