Medium
9 : 25 :: 64 : ?
Explanation
Explanation
The square roots of the first pair are 3 and 5, a gap of 2. The square root of 64 is 8, so following the same gap of 2, the next square root is 10, giving 10 squared = 100.
PRO TIP
Re-check your working by substituting the answer back into the original question.