Answer: 
579600J 
Step-by-step explanation: 
Given parameters: 
Height of the building = 828m 
Weight of the man = 700N 
 
Unknown: 
Work done by the man = ? 
 
Solution: 
 
The work done by the man is the same as the potential energy expended. 
 
 Work done: 
 
 Work done = Weight x height = 700 x 828 
 
 Work done = 579600J