Question

$\sqrt{841} =$

• A. 29
• B. 31
• C. 27
• D. 23

Answer 1

Answer:

A. 29

Method of Calculation

• To find the square root of 841, note that it is a three-digit number between the squares of 20 (400) and 30 (900).
• Since the last digit of 841 is 1, the square root must end in either 1 or 9 (because 1*1=1 and 9*9=81).
• Test the potential candidates: 21 * 21 = 441 (too low) and 29 * 29 = 841.

Key Mathematical Facts

• 841 is the square of 29 (29² = 841).
• It is an odd number and a perfect square.
• In prime factorization, 841 is expressed as 29 × 29 or 29².
• Candidates should memorize squares up to 30 to solve such problems quickly in time-bound examinations.