Răspuns :
Notam cu a, b si c cele 3 unghiuri ale triunghiului. Stim ca a+b+c=180°
Prima situatie:
a=67°45'
67° 45'+b+c=180°
b+c=180° - 67° 45'
b+c=179°60' - 67° 45'
b+c=112°15'
b=c=112°15' : 2
b=c=56°07'30''
A doua situatie
b=c= 67° 45'
a=180° - 2×67°45'
a=180° - 134°90'
a=180° - 135°30'
a=179°60' - 135°30'
a=44°30'
Prima situatie:
a=67°45'
67° 45'+b+c=180°
b+c=180° - 67° 45'
b+c=179°60' - 67° 45'
b+c=112°15'
b=c=112°15' : 2
b=c=56°07'30''
A doua situatie
b=c= 67° 45'
a=180° - 2×67°45'
a=180° - 134°90'
a=180° - 135°30'
a=179°60' - 135°30'
a=44°30'
1) ΔABC - isoscel = > ∡B≡∡C si ∡A = 67°45'
∡B≡∡C=(180° - 67°45') : 2
= (179°60' - 67°45') : 2
= 112°15' : 2
= 112°14'60'' : 2
= 56°07'30"
2) ΔABC - isoscel si ∡B≡∡C = 67° 45'
∡A = 180° - 2·67°45'
= 180° - 134°90
= 180° - 135°30'
= 179°60' - 135°30'
= 44°30'
∡B≡∡C=(180° - 67°45') : 2
= (179°60' - 67°45') : 2
= 112°15' : 2
= 112°14'60'' : 2
= 56°07'30"
2) ΔABC - isoscel si ∡B≡∡C = 67° 45'
∡A = 180° - 2·67°45'
= 180° - 134°90
= 180° - 135°30'
= 179°60' - 135°30'
= 44°30'
