This can be calculated as follows: dihedral angle 150 degrees, radius 1, root number 3. . . Then the radius of the circumscribed circle of the triangle composed of dihedral angle and two diameters is the radius of the sphere, and the side corresponding to 150 degree is the root number 28.

Using the sine theorem again, the radius of the circumscribed circle is the root number 28. . . So the surface area is 4π r 2 = 1 12π.