In mathematics, two variables areproportional if there is always aconstant ratio between them. Theconstant is called the coefficient ofproportionality or proportionality constant. ... x and y are directlyproportional if the ratio yx is constant.
In other words, the constant of proportionality is also the slope, **m**, rate of change, etc.
)²h=π*15²30=π225*30=6750π (~20250in³)