Please explain your answers.
S1: Key here is to realize that triangle ABC isnt said to be inscribed, so we cant assume its a right triangle.
S2: says its a right triangle b/c C=18pi. (if any two points equal the diameter of a circle of a triangle, then that triangle is inscribed).
But we dont know the other sides
Together we can assess its a 30, 60, 90 triangle.