<prompt> Mistari l na m ni sambamba kwa kila mmoja. mangle A 120circ, na mangle B 150circ. Ni idadi gani ya digrii katika mangle C?asyukubwa 100; h halisi 1.2; currentpen fontsize10pt;drawLebol,Relative1,0,0--1,0,E;kuchoraLebom,Jamaa1,0,-h--1,-h,E;chora0,-h--h2cos150pi180,sin150pi180 0,-h;choraLeboC,Jamaa1,0,0--hsqrt32cos-120pi180,sin-120pi 180, W;leboA,0,0,N; leboB,0,-h,S;lebo120circ,0,0,SE; lebo150circ,0,-h,NE;asy  <response>: Tunachora sehemu overlineCD kama inavyoonyeshwa sambamba na mistari l na m.asyukubwa 200; h halisi 1.2; currentpen fontsize10pt;drawLebol,Relative1,0,0--1,0,E;kuchoraLebom,Jamaa1,0,-h--1,-h,E;chora0,-h--h2cos150pi180,sin150pi180 0,-h;choraLeboC,Jamaa1,0,0--hsqrt32cos-120pi180,sin-120pi 180, W;leboA,0,0,N; leboB,0,-h,S;lebo120circ,0,0,SE; lebo150circ,0,-h,NE;jozi D hsqrt32cos-120pi180,sin-120pi180 2,0;kuchoraD -- D-2,0;nukta D;leboD,D,E;asyTangu overlineCDparallel l, tuna angle ACD 180circ - angle A 60circ. Kwa kuwa overlineCDparallel m, tuna angle BCD 180circ - angle B 30circ. Kwa hiyo, angle ACB angle ACD angle DCB 60circ 30circ 90circ. 