Question

Rezolvati amandoua probleme .Dau si coroana! cat mai repede

Answer 1

16.

ABC+BCD+CDA+DAB=360

ABC=DBA+DBC=40+70=110

ABC=CDA=110

BCD=DAB=X

110+X+110+X=360

220+2X=360

2X=140

X=70=BCD=DAB

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ACB=?

ABC=110

CAB=20

(suma unghiurilor intr-un triunghi este 180)

ABC+CAB+ACB=180

110+20+ACB=180

130+ACB=180

ACB=50

CDB=?

DBC=70

BCD=70

BCD+DBC+CDB=180

70+70+CDB=180

140+CDB=180

CDB=40

BDA=?

DBA=40

DAB=70

DAB+DBA+BDA=180

40+70+BDA=180

110+BDA=180

BDA=70

DAC=?

ADC=110

te uiti pe desen si poti observa ca:  

DAC=BCA , deci DAC=50

CDB=ABD

CAB=DCA

BDA=CBD  

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17.ABCD,ABEF

CBE=DAF

m(DAB)≡m(FAB)

AD≡BC

AF≡BE    din astea 3 ⇒ m(DAF)≡m(CBE)