A.L=π(Rt+t/2)/180° B.L=[π(Rt+t/2)α]/180° C.L=(Rt+t/2)α/360° D.L=[π/(Rt+t/2)α]/180°
A.L=[π(Rt-t/2)α]/180° B.L=[π(Rt+t/2)α]/180 C.L=(Rt+t/2)α/180° D.L=[π/(Rt+t/2)α]/180°
A.L=A+B+1.5t B.L=A+B-1.5t C.L=A-B-1.5t D.L=A-B-1.5/t