Cu,figura,in,fata,observam,ca
m(∡A'AC)=180°-(90°+40°)=180°-130°=50°=>m(∡A'AB)=80°-50°=30°
Notam,piciorul,perpendicularei,din,C,pe,AB,cu,C'
In,Δdr.BC'C,m(∡C'CB)=180°-(90°+60°)=180°-150°=30°
=>In,Δdr.HA'A,m(∡A'HC)=180°-(90°+30°)=180°-120°=60°