a) arcAB + arcBC + arcCD + arcDA = 360 ⇒ arcDA = 40 grade
mas arc BCD = 60 + 120 = 180 grd. ⇒ BD = diametru
mas arc ADC = 40 + 120 = 160grd. mas arc DAB = 4 + 140 = 180 grd.
mas arc ABC = 140 + 60 = 200grd.
b) mas<A = (mas arcBCD)/ 2 = 90grd. mas<B = mas arcCDA /2 = 80 grd.
mas<C = mas arc DAB /2 = 90grd. mas<D = masarcABC/2 = 100 grd
c) mas< ABD = masarcAD/2 = 20 grd. mas< BAC = masarcBC/2 = 30 grd.
mas< DBC = masarcDC/2 = 60 grd. mas<BCA = masarcAB/2 = 70 grd.
mas<ACD = masarcAD/2 = 20grd. mas<BDC= masarcBC/2 = 30 grd.
mas<ADB = masarcAB/2 = 70grd. mas<DAC = masarcDC/2 = 60grd.