What is the approximate height of the tower in meters?

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.