Probability in a given distribution

I have the following distribution:

a=0.215775;
b=1.76885;
c=2.28023;

edistT=StudentTDistribution[a,b,c]

I would like to calculate, numerically, the value, pr above which the probability drops to, let us say, 10%. I tried the following:

NSolve[NProbability[x >= pr, x [Distributed] edistT] == 0.1, pr]

But I only get a series of errors.