60 (number) geometry, it is the number of seconds in a minute, and the number of minutes in a degree. In normal space, the three interior angles of an equilateral triangle each measure 60 degrees, adding up to 180 degrees. Because it is divisible by the sum of its digits in base 10, it is a Harshad number. A number system with base 60 is called sexagesimal (the original meaning of "sexagesimal" is sixtieth). It is the smallest positive integer that is written with only the smallest and the largest digit of base 2 (binary), base 3 (ternary) and base 4 (quaternary).
1 in 60 rule is required, the numbers work out with the same rule: 1% over 1 NM ≈ 60' It is also useful to find out the lateral deviation from a given VOR course or radial: Each dot on a VOR indicator represents 2° of deviation, or 200' per dot per DME. There are other applications to this rule. One such application is time drift. An hour is equal to 60 minutes, and a minute is equal to 60 seconds, so some other relationships between angle and time can be observed. If a pilot is flying a leg of 120 miles and finds