Question

Find the square of $86$.

• A. $5684$
• B. $7396$
• C. $6629$
• D. $3436$

Answer 1

Answer: (B)

$7396$

$(86{)}^2$ $\to$ $(80+6{)}^2$

$(80+6{)}^2$ $\to$ $(80{)}^2$ $+$ $(2\times 80\times 6)$ $+$ $(6{)}^2$

$(80+6{)}^2$ $\to$ $6400$ $+$ $960$ $+$ $36$

$(80+6{)}^2$ $\to$ $7396$

Hence, Option B is correct.