Two poles of height 6 meters and 11 meters stand on a plane ground. If the distance between their feet is 12 meters then find the difference in the distance between their tops:  Choose the correct choice from the following:
A) 12 m  B) 5 m  C) 13 m  D) 11 m  E) 12 m

Rationale: distance between their tops = sqrt ( 12 ^ 2 + ( 11 - 6 ) ^ 2 ) = sqrt 169 = 13 m answer : c
Answer: C