Medians
A median joins a vertex to the midpoint of the opposite side. The three medians intersect at the centroid.
Altitudes
An altitude is a perpendicular segment from a vertex to the line containing the opposite side.
Exterior Angles
An exterior angle is formed by one side and the extension of an adjacent side.
Angle Bisectors
An angle bisector divides one of the triangle's angles into two equal angles.
Interior Angle Sum
The sum of the interior angles of any triangle is always 180 degrees.
Pythagorean Theorem
In a right triangle, a² + b² = c². Drag vertices to form a right triangle.