解，设半径为r，﹙r-29﹚²+81²=r²，r=127.62, 设圆心角=b r²×0.5sinb=﹙127.62-29﹚×0.5×162.sinb=0.98,b=arcsin0.98,l弧形=arcsin0.98/360°×2πr=801.45arcsin0.98/360°
