standard_description: Prove theorems about lines and angles. Theorems include: vertical angles are congruent; when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent; points on a perpendicular bisector of a line segment are exactly those equidistant from the segment’s endpoints.
problem_activity: Circle
$$A$$
is shown below.
[IMG]
Draw two diameters of the circle.
Identify the shape defined by the end points of the two diameters.
Explain why this shape is always the result.


aligns: no