<prompt> Katika mchoro, thamani ya y ni nini?asychora0,0--18,0,nyeusiupana wa mstari1;chora18,0--18,-6,nyeusiupana wa mstari1;chora0,0--4,6--18,-6,nyeusiupana wa mstari1;chora18,0--18,-0.5--17.5,-0.5--17.5,0--mzunguko,mweusiupana wa mstari1;lebo80circ,4.5,5,S;lebo60circ,1,0,NE;leboycirc,18.25,-5,NW;asy  <response>: Kwa kuwa pembe ABC pembe BAC pembe BCA180circ na angle ABC80circ na angle BAC60circ, kisha pembe BCA40 mduara.asychora0,0--18,0,nyeusiupana wa mstari1;chora18,0--18,-6,nyeusiupana wa mstari1;chora0,0--4,6--18,-6,nyeusiupana wa mstari1;chora18,0--18,-0.5--17.5,-0.5--17.5,0--mzunguko,mweusiupana wa mstari1;lebo80circ,4.5,5,S;lebo60circ,1,0,NE;leboycirc,18.25,-5,NW;lebo40circ,9.75,0,NW;leboA,0,0,W;leboB,4,6,N;leboC,11,0,SW;leboD,18,0,N;leboE,18,-6,SE;asyKwa kuwa angle DCE pembe BCA 40circ, na tukiangalia pembetatu CDE, tunaona kwamba angle DCE angle CED 90circ kisha 40circ y circ 90circ au y50. 