This week in class we are PARCC testing and using a block schedule.  We typically have an 8 period 50 minute schedule, so I am able to get in some good exploration activities.  First we practiced using construction tools to construct the perpendicular bisectors of a triangle.  We found the circumcenter and circumscribed a triangle about the circle.  It was interesting to see how students excelled at this activity (hands-on application) that do not traditionally do well in class.
To extend the idea of perpendicular bisectors and circumcenters of triangles, I designed a coordinate geometry activity.  Feel free to use this activity. Exploring with the circumcenter

I will re-post with a summary of the class activity.

Objective: Use coordinate geometry as a method for finding the intersection of perpendicular bisectors of a triangle, the circumcenter.  Write the equations of the lines of the perpendicular bisectors of sides of a triangle.  Use the circumcenter to write the equation of a circle that is circumscribed about the given triangle.