Why is x = 4 a solution to the proportion StartFraction 14 over x EndFraction = StartFraction 56 over 16 EndFraction?

1.because 56 divided by 14 is equal to 4
2.because 56 divided by 16 is equal to 4
3.because if you substitute 4 into the equation for x and cross multiply, you get 196 = 196
4.because if you substitute 4 into the equation for x and cross multiply, you get 224 = 224

1 answer

To determine why \( x = 4 \) is a solution to the proportion \(\frac{14}{x} = \frac{56}{16}\), let's analyze the given options:

  1. Option 1: "because 56 divided by 14 is equal to 4"
    This is incorrect. \( \frac{56}{14} = 4 \), but this does not address the relationship between the fractions in the proportion.

  2. Option 2: "because 56 divided by 16 is equal to 4"
    This is incorrect. \( \frac{56}{16} = 3.5 \), so this does not work.

  3. Option 3: "because if you substitute 4 into the equation for x and cross multiply, you get 196 = 196"
    This is correct. If we substitute \( x = 4 \), we have:
    \[ \frac{14}{4} = \frac{56}{16} \]
    Cross-multiplying gives us:
    \[ 14 \cdot 16 = 4 \cdot 56
    \]
    Calculating both sides:
    \[ 224 = 224
    \]
    So it holds true.

  4. Option 4: "because if you substitute 4 into the equation for x and cross multiply, you get 224 = 224"
    This is also correct; however, it is just stating the result and not clarifying it in the same way as option 3.

Among the options provided, Option 3 is the most informative answer, as it explains the process of substituting 4 for \( x \) and shows the cross multiplication leading to the equality.

Thus, the best answer is: 3. because if you substitute 4 into the equation for x and cross multiply, you get 196 = 196.

(There's a bit of confusion here since \( 14 \times 16 = 224 \) and \( 4 \times 56 = 224 \) making Option 4 also valid in an alternative context, if focusing on the multiplication outputs.)