∫ The passing rate of students' math scores (Grade C and above) is 77.5%.

∴11+14+x1+14+9+x = 77.5%, x=6 people.

The number of students selected in ∴ * * * is:11+14+6+9 = 40.

As can be seen from the figure, the number of D-level students is 9.

The percentage of the number of D-level students in the sample is 9-40 = 940.

∴ The central angle of the number of D students in the sector statistical chart is 940× 360 = 8 1,

So the answer is 40,6,81.

(2) According to the figure, there are 1 1 person in Grade A, accounting for1140 =1/40.

∴ The total number of A-level mathematics subjects in the county =1140x11000 = 3025.

So the answer is 3025.