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Finding the Fourth Proportional to 426.96, 639.72 and 391.32

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Solution

The fourth proportional to 426.96, 639.72 and 391.32 is: 586.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.96 : 639.72 = 391.32 : x
  2. Step 2: Convert to fraction form
    426.96/639.72 = 391.32/x
  3. Step 3: Cross multiply
    426.96x = 639.72 × 391.32
  4. Step 4: Simplify right side
    426.96x = 250,335.23
  5. Step 5: Solve for x
    x = 250,335.23/426.96
  6. Step 6: Final answer
    x = 586.32

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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.