standard_description: Partition circles and rectangles into two and four equal shares, describe the shares using the words halves, fourths, and quarters, and use the phrases half of, fourth of, and quarter of. Describe the whole as two of, or four of the shares. Understand for these examples that decomposing into more equal shares creates smaller shares.
problem_activity: Task
Suppose we are given a circle of radius $r$.  The goal of this task is to construct an equilateral triangle whose three vertices lie on the circle.
Suppose $\overline{AB}$ is a diameter of the circle.  Draw a circle with center $A$ and radius $r$ and label the two points of intersection of the circles $P$ and $Q$ as pictured below:
[IMG]
Show that $m(\angle ABP) = 30$ and $m(\angle ABQ) = 30$.
Show that
$\triangle PBQ$ is an equilateral triangle inscribed in the given circle.


aligns: no