Evan is 1.8 metres tall. He walks between two lampposts that are 5 metres apart and notices his shadow from one of the lampposts just touches the base of the other. He also notices that the ratio of his height to the height of the lamppost is 2 to 5. How far is he from each lamppost?
(I understand so far that the lamppost is 4.5 metres tall and that I have to do something with the triangle shape formed-- but I missed the lesson so please, help?)