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Finding the Fourth Proportional to 642.39, 962.15 and 398.40

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Solution

The fourth proportional to 642.39, 962.15 and 398.40 is: 596.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.39 : 962.15 = 398.40 : x
  2. Step 2: Convert to fraction form
    642.39/962.15 = 398.40/x
  3. Step 3: Cross multiply
    642.39x = 962.15 × 398.40
  4. Step 4: Simplify right side
    642.39x = 383,318.57
  5. Step 5: Solve for x
    x = 383,318.57/642.39
  6. Step 6: Final answer
    x = 596.71

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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.