<prompt> Pembetatu ABC na ABD ni isosceles na ABACBD, na overlineBD hupitia overlineAC kwa E. Ikiwa overlineBDperpoverlineAC, basi ni nini thamani ya angle Cangle D? asykuagiza olympiad; kuagiza jiometri; ukubwa 150; defaultpenlinewidth0.8;kuchoraasili--dir70--2Cos70,0--mzunguko;kuchoraasili--dir20--dir70--mzunguko;jozi E makutanoasili--dir20,dir70--2Cos70,0;nuktaE,E;jozi A dir 70;jozi B asili;jozi C 2Cos70,0;jozi D dir 20;nuktaA,A,N;nuktaB,B,SW;nuktaC,C,SE;nuktaD,D,E;choraalama ya kuliaB,E,A,1.5;asy  <response>: Acha angle ABDx na angle BACy. Kwa kuwa pembetatu ABC na ABD ni isosceles, angle C180circ-y2 na angle D180circ-x2. Kisha, tukibainisha kuwa xy90circ, tuna angle Cangle D360circ-xy2135circ. asy kuagiza olympiad; kuagiza jiometri; ukubwa 150; defaultpenlinewidth0.8; kuchoraasili--dir70--2Cos70,0--mzunguko; kuchoraasili--dir20--dir70--mzunguko; jozi E makutanoasili--dir20,dir70--2Cos70,0; nuktaE,E; jozi A dir 70; jozi B asili; jozi C 2Cos70,0; jozi D dir 20; nuktaA,A,N; nuktaB,B,SW; nuktaC,C,SE; nuktaD,D,E; choraalama ya kuliaB,E,A,1.5;lebox,B0.06,0.07,NE;leboy,A-0,.1,S; asy 