standard_description: Compose two-dimensional shapes (rectangles, squares, trapezoids, triangles, half-circles, and quarter-circles) or three-dimensional shapes (cubes, right rectangular prisms, right circular cones, and right circular cylinders) to create a composite shape, and compose new shapes from the composite shape. (Students do not need to learn formal names such as “right rectangular prism.”)
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