Tutoring math, you don’t see this very often these days.  The math tutor recalls learning it in Math 12.

Let’s imagine you have 32.65 degrees.  In the “old days”, it might have been stated as 32 degrees, 39 minutes.  It was gotten this way:

0.65×60=39 minutes.

The “minutes” come from the decimal part of the degree measurement.  Since there are 60 minutes in a degree, take the decimal part of the degrees measurement and multiply by 60.  It’s the same as realizing that 0.25 hours (which is, of course, a quarter of an hour) is 15 minutes:

0.25×60=15 minutes.

What if, after multiplying by 60, you still get a decimal?  That resulting decimal can be converted to seconds by mutliplying by 60 once again.

Example:  Convert 56.87 degrees to degrees, minutes, seconds.

First, use the decimal part to get the minutes:

0.87×60=52.2 minutes.

Now, use the decimal from the minutes to get seconds:

0.2×60=12 seconds.

56.87 degrees is 56 degrees, 52 minutes, 12 seconds.  You can write it  56°52’12”.

To my knowledge, mariners still use minutes and seconds.  High school math students may use them in the future.  When something is taken out of the math curriculum, it often returns years later….

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.