Parallelograms-3: Concurrency of Altitudes and the Euler line!
Channel: Aha Problems
Date: 2024-03-08

Have you ever wondered why 
- altitudes of a triangle meet at a common point (orthocentre)?
- Orthocentre, Circumcentre and Centroid of a triangle lie on a common straight line?

In this video, we continue the parallelogram series. We only have a set of parallel lines feature in this video. And we will use this to get more parallelograms in the next video. 

The facts proved in this video are routinely used in maths olympiad exams. It is considered as basic knowledge for IOQM, RMO, INMO, AMC, AIME, USAMO, and IMO.