The sum of the squares of two consecutive natural numbers is 313 then numbers are

Answer

The sum of the squares of two consecutive natural numbers is 313 then numbers are
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Hint: Let the smaller number be $a$,then the second number will be $a+1$. Square these and add them and then equate the sum to 313. Then solve for $a$.Complete step-by-step answer:Let the smaller number be $a$. Now since the numbers are consecutive, the second number will be $a+1$.We are given that the sum of their squares is equal to 313.${{a}^{2}}+{{\left( a+1 \right)}^{2}}=313$ …(1)We know that ${{\left( x+y \right)}^{2}}={{x}^{2}}+{{y}^{2}}+2xy$. We will use this to simplify ${{\left( a+1 \right)}^{2}}$${{\left( a+1 \right)}^{2}}={{a}^{2}}+1+2a$We will substitute this in equation (1)${{a}^{2}}+{{a}^{2}}+1+2a=313$$2{{a}^{2}}+2a+1=313$$2{{a}^{2}}+2a-312=0$Divide this by 2, we will get the following:${{a}^{2}}+a-156=0$This is a quadratic equation in $a$.We know that $x=\dfrac{b\pm \sqrt{{{b}^{2}}-4ac}}{2a}$where $a{{x}^{2}}+bx+c=0$ is a quadratic equation in $x$ .Using this, we get the following:$a=\dfrac{-1\pm \sqrt{{{\left( -1 \right)}^{2}}-4\times 1\times \left( -156 \right)}}{2\times 1}$ $a=\dfrac{-1\pm \sqrt{1+624}}{2}$$a=\dfrac{-1\pm \sqrt{625}}{2}$$a=\dfrac{-1\pm 25}{2}$$a=\dfrac{-26}{2},\dfrac{24}{2}$$a=-13,12$Since, in the question we need positive integers so we will select $a=12$So $a+1=13$Hence, the required consecutive positive integers are $12$ and $13$.Note: You can check whether your answer is correct or not by substituting $a=12$ and $a+1=13$ in the given equation ${{a}^{2}}+{{\left( a+1 \right)}^{2}}=313$. We get the following:${{12}^{2}}+{{13}^{2}}=144+169=313$. So our answer is correct.

The sum of the squares of two consecutive natural numbers is $$313$$. Then the numbers will be:

  • A

    $$12, 13$$
  • B

    $$13, -12$$
  • C

    $$12, -13$$
  • D

    $$-12, -13$$
Given: sum of the squares of two consecutive natural numbers is 313

To find the numbers

Sol: Let 1 number be $$x$$. Since the numbers are consecutive, the other number would be $$ x + 1$$.

Square both and add together to equal 313.

$$x^2 + (x+1)^2 = 313$$

$$x^2 + x^2 + 2x + 1 = 313$$

$$2x^2 + 2x - 312 = 0$$

$$x^2 + x - 156 = 0$$

$$(x - 12)(x + 13) = 0$$

$$x = 12, x = -13$$

given numbers are natural . so $$ x= 12$$ and $$x+1=13$$ are the two numbers.