Question

Which is the lower consecutive natural number forming the square 13?

(a) 85

(b) 84

(c) 83

(d) 82

This question was posed to me in my homework.

This intriguing question originated from Patterns in Squares of Numbers in division Squares and Square Roots of Mathematics – Class 8

Answer 1

Right option is (b) 84

Easy explanation: The square of number 13 is formed by two consecutive natural numbers and they are 84 & 85. If we need to find the lower number (i.e.84 in this case) we can calculate like this, \(\frac{13^2-1}{2}=\frac{169-1}{2}=\frac{168}{2}\)=84.