3.) A/3 = B/4 = C/5 = D/6 = 360°/18 = 20 ⇒A = 60°, B = 80°, C= 100°, D= 120°
5) 0,(3)·A = 0,25B = 0,125C = 0,(1)D
A/3 = B/4 = C/8 =D/9 = 360° /24 = 15° ⇒A = 45°; B = 60°; C = 120°; D = 135°
4) mas ∡CAB = mas∡DAB - mas∡DAC = 57°
mas∡ACD = 180° - (105°+28°) = 47°
mas∡DCB = mas∡ACD + mas∡ACB = 117°
mas∡B = 360° - (85°+105°+117°) =53°
