Question

In triunghiul ABC m(A)=60 grade , m(C)=70 grade , [BD] este bisectoarea unghiului B si DE paralel BC, E apartine [AB] . Aflatii m(B), m(BDC),m(AED),m(EDB). VA ROG FRUMOSS !! DAU COROANA !!

Answer 1

∡B=180-∡A-∡C=180-60-70

∡B=50°

1) ∡BDC=180-∡EDB-∡EDA

∡EDB=∡DBC alterne int. ED║BC si BD secanta

∡DBC=∡ABC/2 = 25° BD e bisectoare

∡ADE=∡ACB=70° corespondente

relatia 1) devine

∡BDC=180-25-70

∡BDC=85°

∡AED=∡ABC=50°, corespondente

∡EDB=∡DBC=25° alt. interne