11. The coordinates of endpoint A are A(5, -15). The midpoint of AC is B(5, -8). Find the coordinate of endpoint C. (1 point work, 1 point x2, one point y2)
12. Find the distance between A(12, 6) and B(-8, 18). Leave your answer in simplest radical form. (1 point work, 1 point answer)
13. Find the area of a circle with diameter 8 in. Round to the nearest tenth. (1 point answer, 1 point units)