Can a right triangle be formed using these squares

The answer is yes. all 3 of those triangles have perfect square roots, being 5, 12, and 13 respectively. I hope this helps! Could I possibly get brainliest?

arc length = radius * x ( in radians)

6 * pi = 18 * x

divide by 18 on each side

6 pi / 18 = x

pi/3 = x

the angle is pi / 3 radians

or   60 degrees