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Finding the Fourth Proportional to 426.72, 639.74 and 392.55

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Solution

The fourth proportional to 426.72, 639.74 and 392.55 is: 588.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.72 : 639.74 = 392.55 : x
  2. Step 2: Convert to fraction form
    426.72/639.74 = 392.55/x
  3. Step 3: Cross multiply
    426.72x = 639.74 × 392.55
  4. Step 4: Simplify right side
    426.72x = 251,127.97
  5. Step 5: Solve for x
    x = 251,127.97/426.72
  6. Step 6: Final answer
    x = 588.51

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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.