Răspuns :
inΔADB:
∡BAD+∡ADB+∡DBA=180 grade
110+29+∡DBA=180
139+∡DBA=180
∡DBA=180-139
∡DBA=41 grade
∡ABC=∡DBA+DBC
110=41+∡DBC
∡DBC=110-41
∡DBC=69 grade
∡ADC=∡ADB+∡BDC
∡ADC=29+56
∡ADC=85 grade
∡A+∡B+∡C+∡D=360grade
∡110+110+∡C+85=360
305+∡C=360
∡C=360-305
∡C=55 grade
∡BAD+∡ADB+∡DBA=180 grade
110+29+∡DBA=180
139+∡DBA=180
∡DBA=180-139
∡DBA=41 grade
∡ABC=∡DBA+DBC
110=41+∡DBC
∡DBC=110-41
∡DBC=69 grade
∡ADC=∡ADB+∡BDC
∡ADC=29+56
∡ADC=85 grade
∡A+∡B+∡C+∡D=360grade
∡110+110+∡C+85=360
305+∡C=360
∡C=360-305
∡C=55 grade
![Vezi imaginea Lonely11](https://ro-static.z-dn.net/files/d9a/4959589c50bd5a3d72379673781f3d66.png)