Got this question in one of the MGMAT CAT
For the triangle shown above, where A, B and C are all points on a circle, and line segment AB has length 18, what is the area of triangle ABC?
(1) Angle ABC measures 30°.
(2) The circumference of the circle is 18.
(Could not paste the image :()
In its explanation it assumes AB as the diameter of the circle which is not correct, but still gives answer as C. Please correct it :)