The sum of the squares of two consecutive positive numbers is 61. What is the smaller number?

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Oddman answered
If s represents the smaller number you can write an equation for s like this   s^2 + (s+1)^2 = 61   2s^2 + 2s - 60 = 0    (subtract 61, collect terms)   s^2 + s - 30 = 0    (divide by 2)   (s-5)(s+6) = 0    (factor)  The smaller number is 5.
Check   5^2 + 6^2 = 25 + 36 = 61  Consider that the two numbers are almost equal. Thus, the value 61 is about double the square of one of those equal numbers. √(61/2) ≈ 5.5. Since we are looking for consecutive integers, this value between 5 and 6 suggests that the two integers involved are 5 and 6. A quick check (25+36=61) reveals 5 to be the correct choice for the smaller number.

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