Desargues' Theorem
-Desargues' Theorem states that if two lines are in perspective centrally, then they will be in perspective axially.
-To prove this, first notice one triangle with the points A, B, and C; then notice the other triangle with the points A', B', and C', as shown below.
-Next, notice lines through A and A', B and B', and C and C'. The point of intersection that lies between the three lines is called the Center of Perspectivity.
-Then, observe the lines between corresponding points (ex. The intersection point between the line through A and B, and the line through A' and B'). All of those intersection points make a straight line that is called the Axis of Perspectivity
-Interact with the work below by moving around the red points.