Determine the integral from 0 to 1 of 3/(sqrt(4-x^2)) dx

Here's what I did:

3/ sqrt(4(1-(x^2)/4))

(3/2)(1/(sqrt(1-(x/2)^2))

3/2 0 to 1 1/(sqrt(1-u^2)) where u=x/2

3/2 (sin^-1(x))] 0 to 1

(3/2)*(pi/2)=3pi/4

Did I do this correctly? If not, could someone please point out my mistakes? Thanks in advance!