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:

• A. 4%
• B. 2%
• C. 4.04%
• D. 2.02%

Answer: (C)

100 cm is read as 102 cm. ∴ A1 = (100 x 100) cm2 and A2 (102 x 102) cm2. (A2 - A1) = [(102)2 - (100)2] = (102 + 100) x (102 - 100) = 404 cm2. ∴ Percentage error = ❨ 404 x 100 ❩% = 4.04%