The equation is 15*w*14 = 2730
We simply multiply length, width and height to get the volume of the rectangular block.
That equation becomes 210w = 2730 because 15*14 = 210
From here, we divide both sides by 210
You should end up with w = 13
As a check, 15*w*14 = 15*13*14 = 2730 which confirms we have the correct replacement for w.