The notation used is 1315 minutes and 36 secs. There are 60 minutes in 1 degree So in 1315 minutes we have X degrees So X * 60 = 1315 * 1 X = 21.916 degrees Also there are (60*60) seconds in 1 degree In 36 seconds we have X degrees. Hence X * 3600 = 36 * 1 X = 36/3600 = 0.01 degrees. So we have 21.916 + 0.01 = 21.926 degrees. But Suppose the question meant to write 13°15'36" instead if 1315'36" Then to calculate the decimal degrees, we follow the same method like the one above. So we have 13 + (15/60) + (36/60) = 13 + 0.25 + 0.6 = 13 85