Question

Choose appropriate number for fourth place
36 : 64 :: 81 : ?

• A. 25
• B. 16
• C. 121
• D. 49

Answer 1

Answer: (C)

121

Logic for the above terms are $x^2:(x+1{)}^2$

$6^2=36$
$(6+2{)}^2=64$
same as
$9^2=81$
$(9+2{)}^2=121$

Hence the correct answer is option $C$.