An error 2% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is?
Pick one
A) 4.04 %
B) 5 %
C) 7 %
D) 9 %
E) 11 %

Rationale: "100 cm is read as 102 cm . a 1 = ( 100 x 100 ) cm 2 and a 2 ( 102 x 102 ) cm 2 . ( a 2 - a 1 ) = [ ( 102 ) 2 - ( 100 ) 2 ] = ( 102 + 100 ) x ( 102 - 100 ) = 404 cm 2 . percentage error = 404 x 100 % = 4.04 % 100 x 100 a )"
Answer: A