Answer:
5sqrt3
Step-by-step explanation:
Using the pythagorean theorem, we have a^2+4^2=9^2
a^2 + 16 = 81
a^2 = 75.
a = sqrt75.
75 = 25*3. 25 is a perfect square, so sqrt75 = 5sqrt3
8.0622577483
pythagorean theorem
