Use similar triangles
distance of man from puddle = 0.5 m.
distance of puddle from tower = 13 - 0.5 = 12.5 meters
so we have 2 similar triangles
one has height 2 m and base 0.5 m and the other has height x m ( the tower) and base 12.5 m
Corresponding sides are in the same ratio, so
2 / x = 0.5 / 12.5
0.5x = 2*12.5 = 25
x = 25 / 0.5 = 50 m
The tower is approx 50 m high.
