Isosceles triangle ABC circumscribes a circle of radius r = 13. Find the angle 0 that minimizes the area of AABC if AB = BC. DEA gure shows an isosceles triangle with a circle inscribed in its base, and has base angles A and C and vertex angle B. The circle has radius r. The median of the triangle and the diameter of the circle coincide. A dashed line perpendicular to one of the legs of the triangle is drawn from the center of the circle. A dashed line is drawn from the center of the circle to one of the vertices of the base. (Use symbolic notation and fractions where needed. Enter your value in units of radians.)