Calculate expansion fan angle with aerospace toolbox

Hello,

I have this problem, shown in the figure, where I need to calculate the angle where the expansion fan is positioned. From experimental images I can see that this angle is 46°, and that the opening angle of the fan is 11.3°.

I'm using the aerospace toolbox to calculate these angles from the prandtl meyer theory and see the differences. I managed to calculate the 11.3° angle using the flowprandtlmeyer.m, calculating mu_final - mu_initial. The problem is that I don't remember how to calculate that 46° angle, and I cannot find any useful information online. Any help?

Thanks