Using a trigonometric relation we can see that RT = 12 units.
How to find the length of the side RT?
Here we want to find the length of the side RT in the right triangle. Notice that this would be the hypotenuse of the triangle.
And we also know the angle T = 60°, and the opposite cathetus of this angle, which has a length of 6√3, then we can use the trigonometric relation:
sin(angle) = (opposite cathetus)/hypotenuse.
Replacing what we know, we will get:
sin(60°) = 6√3/RT
Solving for RT we will get:
RT = 6√3/(sin(60°))
RT = 12