clear
//Given
l=6000*10**-10                       //m
D=0.800                               //m
d=0.200*10**-3                         //m

//Calculation
x2=(3*l*D)/(2.0*d)
x21=(2*D*l)/d

//Result
printf("\n (i) Distance of the second dark fringe is %0.3f  cm", x2*10**2)
printf("\n (ii) Distance of the second dark fringe is %0.3f  cm", x21*10**2)