Question 900923
Two sides are equal, and the base side is 16 inches.  The only way this fits in the circle as described is that the two equal sides meet at a right angle.  The distance from circle center to the vertex opposite the base  (the diameter serving as the base of the triangle) is a radius of the circle, 8 inches.  


The area of this triangle is {{{(1/2)*16*8=64}}} square inches.