<p>It’s 30 degrees, since this is a 30-60-90 special right triangle.
remember? 30-60-90 x-xsqrt3-2x.
You can see this is so because 6 is 2 times 3.</p>
<p>^The hypotenuse is the biggest side…
Which is why the side length of 6 corresponds with the 90 degree angle and the 3 corresponds with the 30 degree angle and the 3*sqrt3 corresponds with the 60 degree angle.</p>