Approximately 0.30 for AA, 0.50 for Aa, and 0.20 for aa.
Work Step by Step
Since a=0.45, A=0.55 since A+a=1. Then, for AA, multiply 0.55x0.55, and for aa, 0.45x0.45. For Aa, see the text on Hardy Weinberg to see that there should be 2Aa=2x0.45x0.55. As a check, AA+2Aa+aa=1, which is true with these answers given.