Calculating distance, speed and time for plotting.

Here is a math triangle. It is very important for me as a future navigator to be able to do calculations quickly and easily.

Here how it works:

You want to know distance. put you finger over the D. What remains is the letters S & T. As the Speed and Time are beside each other, you multiply them to get your distance.

Example: What distance do you travel when you going 7.2 knots for 3 hours?

Solution: Place your finger over the D and multiply the Speed and Time;
                                                                                  7.2 x 3 = 21.6 nautical miles.


Example: What is your speed when you have travelled 8 nautical miles for 4 hours?

Solution: Place your finger over the S and divide Distance by Time;
                                                                         8 / 4 = 2 knots.

Example: How much time did you take, travelling 14.3 miles at 6.4 knots?

Solution: Place your finger over the T and divide the Distance by Speed;
                                                                              14.3 / 6.4 = 2.234375 or 2.2 hours.

What is .2 hours you ask? Good question as the time is the confusing part here.

To convert the .2 hours to minutes you have to multiply .2 by 60 with is 12 minutes so it took you 2 hrs and 12 minutes to travel 14.3 miles at 6.4 knots.

To solve problems when time is hours and minutes, you must convert the minutes to the base ten like in the above example.

You have 2 hours and 22 minutes. To convert the minutes divide them by 60. 22 / 60 = .36666 or .37. This means the time is 2.37 hours.

Example: You travelled 8.8 nautical miles 2.37 hours, what is your Speed?

Solution: Put your finger over the S and divide the Distance by the Time;
                                                                              8.8 / 2.37 = a blistering 3.71 knots.

I have an exam on this shit in two days.