The next number in the last group

pattern recognition

there. I came across a number pattern problem like the one in the following picture. Does anyone happen to know what the ? stands for? Or how can we calculate the number? Thank you.
enter image description here

Best Answer

The third number in each sequence is the sum of the squares of the previous 2. $$2^2+6^2=4+36=40$$ $$3^2+7^2=9+49=58$$ $$6^2+5^2=36+25=61$$

Using this rule, we can do it for the missing number: $$2^2+3^2=4+9=13$$

So the correct answer is (A) 13

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