Use the following information to answer questions 53-55.
In the figure below, a large circle with center O has a diameter AB that is 40 mm long. Point C lies on the large circle such that the measure of ∠ABC is 60°. A diameter of the small circle is AO.
55. The figure is placed in the standard (x, y) coordinate plane so that A has coordinates (-20, 0) and B has coordinates (20, 0). What is the x-coordinate of C ?
Your Answer is
Correct Answer is D
Explanation
Because angle CBA is 60 degrees and OC=OB, triangle OCB is an equilateral triangle. So the abscissa of point C is the average of the abscissas of points O and B, which is 10.