A triangular pipe network is shown in the figure.
The head loss in each pipe is given by $h_f = rQ^{1.8}$, with the variables expressed in a consistent set of units. The value of $r$ for the pipe $AB$ is $1$ and for the pipe $BC$ is $2$. If the discharge supplied at the point $A$ (i.e., $100$) is equally divided between the pipes $AB$ and $AC$, the value of $r$ (up to two decimal places) for the pipe $AC$ should be _______