calculate the mach number after an oblique shockwave

JD88

I am trying to calculate the mach number after an oblique shockwave. The freestream mach number is 2.0 and the angle theta is 25 deg. But on the Theta-Beta-Mach Diagram the line Theta=25deg does not intersect the Mach=2 line. So this means that the angle has exceeded the maximum allowable theta and the shockwave has come detached, right? If it were not detached I would just look up Beta off of the diagram and use it to calculate the normal mach number normal to the shockwave and go from there.

So how would I go about determining the mach number after the oblique shockwave when the angle has exceed the max and the wave is detached?