The centroid is the common intersection of the three medians. A median of a triangle is the segment from a vertex to the midpoint of the opposite side
<>The orthocenter is the common intersection of the three lines containing the altitudes. An altitude is a perpendicular segment from a vertex to the line of the opposite side.The circumcircle is the circumscribed circle of the triangle.
The incenter of a triangle is the point on the interior of the triangle that is equidistant from the three sides.
The incircle is the
inscribed circle of the triangle.
Square, given a side
Isosceles triangle, given base