OC=OD=OA=r=AB/2=6
OE=OA-AE=4
DE²+OE²-OD²=2*OE*DE*cos60°
DE²-4DE-20=0,DE=(4加减根号(16+80))/2=2加减2根号6
舍去负值,DE=2+2根号6
CE²+OE²-OC²=2*OE*CE*cos120°
CE²+4CE-20=0,CE=2根号6-2
CD=CE+DE=4根号6
OC=OD=OA=r=AB/2=6
OE=OA-AE=4
DE²+OE²-OD²=2*OE*DE*cos60°
DE²-4DE-20=0,DE=(4加减根号(16+80))/2=2加减2根号6
舍去负值,DE=2+2根号6
CE²+OE²-OC²=2*OE*CE*cos120°
CE²+4CE-20=0,CE=2根号6-2
CD=CE+DE=4根号6