To find the perimeter, you need the lengths of all 3 legs,
and then you add them up.
Can you find the lengths of the other 2 sides of that triangle ?
Here are a couple of factoids I learned in 1954 and I never forgot:
In a 30°- 60°- 90° right triangle . . .
-- the side opposite the 30° angle (the shorter leg)
is 1/2 the length of the hypotenuse,
and
-- the side opposite the 60° angle (the longer leg)
is (1/2 the length of the hypotenuse) times (√3).
If you have a 30°- 60°- 90° triangle and you know the length
of any one side, then you can find the lengths of the other
two sides with these amazing factoids.