Find the missing lengths of the sides.

Answer:
The second bubble
Step-by-step explanation:
In a 30 60 90 triangle as shown here a is always 1/2 the hypotenuse (Which the hypotenuse is 6) and then just add [tex]\sqrt{3}[/tex] to the end of it to get b
So, lets demonstrate
a = 1/2 * 6 = 3
b = a*[tex]\sqrt{3}[/tex] = a[tex]\sqrt{3}[/tex] = 3[tex]\sqrt{3}[/tex]
So,
a = 3
b = 3[tex]\sqrt{3}[/tex]