做高,设为h;
BC=2(sqrt3-1)h
AB^2=h^2(1+(2-sqrt3)^2)=h^2(8-4sqrt3)
BD*BC=2(sqrt3-1)h*(sqrt3-1)h=h^2(8-4sqrt3)
AB^2=BD*BC;
可得三角形相似,
结果为105°
BC=2(sqrt3-1)h
AB^2=h^2(1+(2-sqrt3)^2)=h^2(8-4sqrt3)
BD*BC=2(sqrt3-1)h*(sqrt3-1)h=h^2(8-4sqrt3)
AB^2=BD*BC;
可得三角形相似,
结果为105°