Question

While finding the square root of 36 by repeated subtraction, in which step does 20 occur?

• A. 3${}^{rd}$
• B. 5${}^{th}$
• C. 4${}^{th}$
• D. 6${}^{th}$

Answer 1

The correct option is C 4${}^{th}$

The sum of first $n$ odd natural numbers is $n^2$. This fact is used to find the square root of a number by repeated subtraction. In finding the square root of 36 by repeated subtraction the steps involved are:-
$\begin{array}{cc}StepNumber& Value\\ 1& 36-1=35\\ 2& 35-3=32\\ 3& 32-5=27\\ 4& 27-7=20\\ 5& 20-9=11\\ 6& 11-11=0\end{array}$
You can clearly see that 20 occurs in the 4${}^{th}$ step.