The circle that passes through all vertices (corner points) of a triangle.

Try moving the points below, and notice:

• the center (called the circumcenter) can be inside or outside of the triangle.

• the center is where three special lines cross: lines that are at right angles to the midpoint of each side of the triangle.

Try moving the points below, and notice:

• the center (called the circumcenter) can be inside or outside of the triangle.

• the center is where three special lines cross: lines that are at right angles to the midpoint of each side of the triangle.