Convert (675.6)8 to hexadecimal. (use base 2 instead of base 10 as the intermediate base for conversion).

1BD.C

Explanation:

Keep in mind that octal number has 3 binary fields where the right field is the number 1, the center field is the number 2 and the left field is the number 4. you need that your 3 fields sum the final octal digit.

For example :

The hexadecimal number has 4 binary fields where the right field is the number 1, the center field is the number 2 , the next center field is the number 4 and the left field is the number 8. you need that your 4 fields sum the final hexadecimal digit.

For example:

Step 1: Split your octal number  in digits and convert to binary form

         6                             7                           5               .                  6

        110                          111                         101              .                110

Step 2: Join your binary number and split in groups of 4 elements from the point (Important note: If you miss some element to complete the groups at the left of the point complete with zero's at the left, else if you miss some element to complete the groups at the right of the point complete with zero's at the right)

binary complete:      110111101.110

binary in groups of 4:

                     1                1011                      1101            .                110

Complete the groups with zero's (Remember the important note):

               0001                1011                      1101            .              1100

Step 3: Calculate the hexadecimal number

                  1                      B                         D               .               C