解決方案:
a是AD⊥BC，豎腳是d
AB = AC = 2cm，∠ABC=30
∴∠ACB=∠ABC=30
∴∠BAC=120，AD=1/2AB=1cm，BD=√3cm
∴BC=2BD=2√3cm
∴S△ABC=1/2BC？AD =√3cm & amp；sup2
如果是1:
s範abec = [(360-120)/360]？S⊙A=2/3？π?2 & ampsup2= 8/3πcm & amp；sup2
s範DBFC=1/2S⊙D=1/2？π?(√3)?& ampsup2= 3/2πcm & amp；sup2
s尹=？S粉絲ABEC+S△ABC- S粉絲DBFC=(7/6π+√3)？cm & ampsup2
在第二種情況下:
s範abec = (120/360)？S⊙A=1/3？π?2 & ampsup2= 4/3πcm & amp；sup2
s範DBFC=1/2S⊙D=1/2？π?(√3)?& ampsup2= 3/2πcm & amp；sup2
s尹=？■粉絲DBFC-(？S粉絲ABEC-S△ABC)=？(1/6π+√3)?cm & ampsup2