Question

in triangle ABC, P is the orthocentre. Prove that in triangle PBC is A.

Answer 1

Given : P is the orthocentre of ΔABC.

Let AP extended, BP extended and CP extended intersect BC, AC and AB at D, E and F respectively.

Then AD⊥BC, BE⊥AC, CF⊥AB.

⇒ AD⊥BC, AB⊥CP, AC⊥BP

Hence A is the orthocentre of ΔPBC.