Răspuns:
11. P=2×(4 dm + 32 cm)=2×(40 cm + 32 cm)=2×72 cm=144 cm
18.
a) ABC = ADC = 40°
DAB = DCB = 180° - 40° = 140°
b) ABC = ADC = 50°
DAB = DCB = 180° - 50° = 130°
c) ABC = ADC = 100°
DAB = DCB = 180° - 100° = 80°
d) ABC = ADC = 70° 30'
DAB = DCB = 180° - 70° 30' = 109° 30'
21.
A+B+C=230°
D=360°-230°
=130°
B=D=130°
A=C=180°-130°=50°
