Question

Predict the square root of $1369$ using Vilokanam method.

• A. $33$
• B. $37$
• C. $43$
• D. $47$

Answer 1

The correct option is B $37$

Square root of $1368$ using vilokamam method

$\Rightarrow$ It's unit digit is $9$, therefore, the unit digit of the square root will be $3$ or $7$.

$\Rightarrow$ Ignoring the last two digits(unit & tens digits) we get $13$

$\Rightarrow$ The greatest No. whose square is less than or equal to $13$ is $3$.

$\Rightarrow$ Adjusting above obtained then unit digits $3$ or $7$ to the right of $3$, we get two numbers $33$ & $37$

$\Rightarrow$ The unique number with unit digit $5$ which lies between $33$ & $37$ is $35$.

$(35{)}^2=(3\times 4)\times 25=$

$(35{)}^2=(3\times 4).2=1225$

by Ekadhikena sutra

Since $1369>1225$, therefore, the required root is $\Rightarrow 37$.