//

//

aa=1.725
ab=1.370
ba=1.560
bb=1.235

A=aa-ab
B=ba-bb

AB=(A+B)/2

printf("\n true difference between A and B is  %0.3f meters',AB)

CB=bb
CA=CB+AB

OCA=1.560
e=OCA-CA

printf("\n amount of collimation error = %0.3f meters',e)