Sophia Brahe was a Danish astronomer in the 16th and 17th century who worked with her brother Tycho Brahe, also astronomer, in the creation of a star catalogue that Kepler used as a source to find the laws on the movement of planets in the Solar System. She made the observations on the lunar eclipse of December 1573. 

Astronomy is one of the oldest sciences and it became more relevant when it was applied to navigation during Europe's Age of Discovery.

We are in an observatory in the highest part of a lighthouse, at 50 m high, and we notice a boat at an angle of 10º (depression angle). What is the distance between the base of the lighthouse and the boat?