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Finding the Fourth Proportional to 717.60, 1,076.40 and 392.79

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Solution

The fourth proportional to 717.60, 1,076.40 and 392.79 is: 589.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.60 : 1,076.40 = 392.79 : x
  2. Step 2: Convert to fraction form
    717.60/1,076.40 = 392.79/x
  3. Step 3: Cross multiply
    717.60x = 1,076.40 × 392.79
  4. Step 4: Simplify right side
    717.60x = 422,799.16
  5. Step 5: Solve for x
    x = 422,799.16/717.60
  6. Step 6: Final answer
    x = 589.19

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.