G.GCI.3 Constructing a Circumcenter
1) Use the POLYGON tool to construct a triangle. 2) Use the PERPENDICULAR BISECTOR (PB) tool to construct the PB's of this triangle's 3 sides. 3) Plot the intersection of these 3 perpendicular bisectors (circumcenter).
Construct a circle centered at the circumcenter that passes through any vertex of this triangle. Why does this circle pass through the other 2 vertices of this triangle?
When you're done (or if you're unsure of something), feel free to check by watching the quick silent screencast below the applet.