Amateur astronomers often approximate angles with an arm out-
stretched. With the hand in this position, one finger's width is approximately
2 degrees, the width of your hand at the knuckles is approximately 10 degrees, and your
hand fully spanned is approximately 20 degrees,. You are on the shore and you see a
boat. With your arm outstretched, the height of its mast is 1 finger's width.
You also know that this boat's mast is 10 metres in height. How far away
is the boat? 30 seconds later you notice the mast is now 2 finger widths in
height. How fast is the boat sailing towards you? Now convert this speed
into knots (look it up).
1 fingers = 2 degrees,
The Attempt at a Solution
I dunno where to start