The perpendicular from A on side BC of a ΔABC intersect BC at D such that DB = 3CD. Prove that 2AB^2 = 2AC^2 + BC^2. The perpendicular from A on side BC of a ΔABC intersect BC at D such that DB = 3CD. Prove that 2AB^2 = 2AC^2 + BC^2. October 5, 2020 [...]