To solve V = lwhV=lwh for ww we need to divide each side of the equation by color(red)(l)color(blue)(h)lh
V/(color(red)(l)color(blue)(h)) = (lwh)/(color(red)(l)color(blue)(h))Vlh=lwhlh
V/(color(red)(l)color(blue)(h)) = (color(red)(cancel(color(black)(l)))wcolor(bue)(cancel(color(black)(h))))/(cancel(color(red)(l))cancel(color(blue)(h)))
V/(lh) = w
w = V/(lh)