Answer:
3
 + 9
Explanation:
In a 30-60-90 triangle, the hypotenuse is twice the short leg.
In this case the hypotenuse is 2*3 = 6 units long.
In a 30-60-90 triangle, the long side is 
 times as long compared to the short side.
So:
long side = short side * 

long side = 3 * 
 = 3

Perimeter = long side + short side + hypotenuse
Perimeter = 3
 + 3 + 6
Perimeter = 3
 + 9