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Finding the Fourth Proportional to 878.78, 1,318.46 and 391.80

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Solution

The fourth proportional to 878.78, 1,318.46 and 391.80 is: 587.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.78 : 1,318.46 = 391.80 : x
  2. Step 2: Convert to fraction form
    878.78/1,318.46 = 391.80/x
  3. Step 3: Cross multiply
    878.78x = 1,318.46 × 391.80
  4. Step 4: Simplify right side
    878.78x = 516,572.63
  5. Step 5: Solve for x
    x = 516,572.63/878.78
  6. Step 6: Final answer
    x = 587.83

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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.