![Explanation of distance-calculation, overview The distance](http://s1.studyres.com/store/data/010607132_1-af0dfc93341ccfec4f0711f5b539125c-300x300.png)
Law of sines and cosines applications
... 2. The top of a lighthouse is 120 meters above sea level. The angle of depression from the top of the lighthouse to a ship is 23º. How far is the ship from the base of the lighthouse? ...
... 2. The top of a lighthouse is 120 meters above sea level. The angle of depression from the top of the lighthouse to a ship is 23º. How far is the ship from the base of the lighthouse? ...
Rule of marteloio
![](https://en.wikipedia.org/wiki/Special:FilePath/Tondo_e_quadro_(Bianco,_1436).jpg?width=300)
The rule of marteloio is a medieval technique of navigational computation that uses compass direction, distance and a simple trigonometric table known as the toleta de marteloio. The rule told mariners how to plot the traverse between two different navigation courses by means of resolving triangles with the help of the Toleta and basic arithmetic.Those uncomfortable with manipulating numbers could resort to the visual tondo e quadro (circle-and-square) and achieve their answer with dividers. The rule of marteloio was commonly used by Mediterranean navigators during the 14th and 15th centuries, before the development of astronomical navigation.