The radius of the arena 13, the radius of the auditorium is twice as large as the radius of the arena

The radius of the arena 13, the radius of the auditorium is twice as large as the radius of the arena, and the radius of the auditorium is 12 meters less than the radius of the Foyer. Find out what is the diameter of a circus building?

The radius of the circus arena is 13 m, and the radius of the auditorium is 2 times larger, which means the radius of the auditorium:
1) 13 * 2 = 26 (m) radius of the auditorium

The radius of the auditorium is 12 meters less than the radius of the foyer, which means that the radius of the foyer is:
2) 26 + 12 = 38 (m) lobby radius

The radius of the foyer is equal to the radius of the circus building, which means that the diameter of the circus building is equal to the diameter of the foyer.
Knowing the radius, the diameter can be calculated by the formula:
D = 2 * R where D – diameter, R – radius
So the diameter of the circus building is:
D = 2 * R = 2 * 38 = 76 (m)

Answer: 76 m.