Read the following SAT test question, then click on a button to select your answer.

In the figure above, inscribed triangle ABC is equilateral. If the radius of the circle is r, then the length of arc AXB is

Correct Answer: A

Here's Why:

An equilateral triangle has three equal sides, so the lengths of the three arcs must be equal, and thus each arc is  of the circumference of the circle. The circumference of the circle is 2r, so the length of arc AXB is of 2r, or .

Difficulty: Medium

Question Type: Standard Multiple Choice