1. It is possible to see two triangles: for tree and for Corett. For Corett's triangle: 1.38 and 1.87; for tree: 3.03 and 'x'. Using fact, that triangle of tree is ~ triangle of Corett, it is possible to make up equation:
1.38:1.87=3.03:x
2. x=1.87*3.03/1.38≈4.1059 meters.
Answer: 4.1059 m.