grid north is west of true

north by 0 degrees, 57 minutes, which is equal to 17 mils. (There are 6,400 mils in a circle.) Magnetic north is east of true north by 8 degrees, which is equal to 142 mils.
*B. What is the difference (in degrees and minutes) between true north (star) and grid north (GN)—in this case, the line to the left of the true North line?

To find the difference between true north and grid north, we need to subtract the angles by which grid north is west of true north from the angle by which magnetic north is east of true north.

Given that grid north is west of true north by 0 degrees, 57 minutes (which is equal to 17 mils) and magnetic north is east of true north by 8 degrees (equal to 142 mils), we can calculate the difference as follows:

1. Convert 0 degrees, 57 minutes to mils:
- Multiply minutes by the number of mils in one minute (0.057 * 6,400 = 365.8 mils)
- Add the result to the degree value in mils (0 degrees + 365.8 mils = 365.8 mils)

2. Subtract the mils value for grid north from the mils value for magnetic north:
- 142 mils - 365.8 mils = -223.8 mils

Since the result is negative, it means that grid north is to the left (west) of true north. The difference between true north and grid north is 223.8 mils.

To convert this value back to degrees and minutes:
- Divide the mils value by the number of mils in one degree (223.8 / 17 = 13.17 degrees)
- The integer value represents the number of whole degrees (13 degrees)
- Multiply the decimal part by 60 to get the minutes (0.17 * 60 = 10.2 minutes)

Therefore, the difference between true north and grid north is approximately 13 degrees and 10.2 minutes.