Lesson: Pieces of Pi

Comment on Pieces of Pi


I am confused by the question. I understand the concept of circumferences and got the bit that the arch 1/6 of the circle. But, at what point in the question did it say that points RTU make up a triangle? Points RTU could be three separate points on the circumference of the circle - couldn't it?

What am I missing here?
gmat-admin's picture

Question link: https://gmatclub.com/forum/the-points-r-t-and-u-lie-on-a-circle-that-has...

You're right to say that the arc is 1/6 of the circle.
This means the central angle of ∆RCU is 60°

Take a look at the image Bunuel created at https://gmatclub.com/forum/the-points-r-t-and-u-lie-on-a-circle-that-has...

Since the central angle of ∆RCU is 60°, we can see that ∆RCU is an EQUILATERAL triangle.
Since all sides are equal in an equilateral triangle, each side has length 4.

Does that help?


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