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Finding the Fourth Proportional to 878.40, 1,318.24 and 391.76

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Solution

The fourth proportional to 878.40, 1,318.24 and 391.76 is: 587.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.40 : 1,318.24 = 391.76 : x
  2. Step 2: Convert to fraction form
    878.40/1,318.24 = 391.76/x
  3. Step 3: Cross multiply
    878.40x = 1,318.24 × 391.76
  4. Step 4: Simplify right side
    878.40x = 516,433.70
  5. Step 5: Solve for x
    x = 516,433.70/878.40
  6. Step 6: Final answer
    x = 587.93

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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.