[?] = $\frac{\lbrack Sl^{3}\rbrack}{\lbrack 4yd^{3}\delta\rbrack} = \frac{\left\lbrack MLT^{- 2} \right\rbrack\left\lbrack L^{3} \right\rbrack\lbrack L^{2}\rbrack}{\left\lbrack MLT^{- 2} \right\rbrack\left\lbrack L^{3} \right\rbrack\lbrack L\rbrack} = \lbrack L\rbrack$