June 2011 Geometry Regents Question?

For the question on the regents with that you had to find the angle and they gave you the ratio of the circle 3:4:5, how much would they took off if you somehow ended up with 40 instead of 30 as your answer? I showed all of my work but somehow ended up writing 9x=360 instead of 12x=360. I think I got every other question right but made a careless mistake there. Will I only lose 1 point?