Răspuns :
A =50⁰
α I β
B C
α β
notat B = 2· α si C = 2·β
Δ ABC , suma unghiurilor A +B +C = 180⁰ ; 50⁰ + 2·α +2·β =180 ⁰
2·α + 2·β =180⁰ - 50⁰ = 130⁰ atunci α + β =65⁰
in Δ BIC suma unghiurilor α + β + <BIC =180⁰
↓
65⁰ + < BIC = 180⁰
mas<BIC = 180⁰ - 65⁰ = 115⁰
α I β
B C
α β
notat B = 2· α si C = 2·β
Δ ABC , suma unghiurilor A +B +C = 180⁰ ; 50⁰ + 2·α +2·β =180 ⁰
2·α + 2·β =180⁰ - 50⁰ = 130⁰ atunci α + β =65⁰
in Δ BIC suma unghiurilor α + β + <BIC =180⁰
↓
65⁰ + < BIC = 180⁰
mas<BIC = 180⁰ - 65⁰ = 115⁰