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Finding the Fourth Proportional to 878.90, 1,318.80 and 391.83

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Solution

The fourth proportional to 878.90, 1,318.80 and 391.83 is: 587.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.90 : 1,318.80 = 391.83 : x
  2. Step 2: Convert to fraction form
    878.90/1,318.80 = 391.83/x
  3. Step 3: Cross multiply
    878.90x = 1,318.80 × 391.83
  4. Step 4: Simplify right side
    878.90x = 516,745.40
  5. Step 5: Solve for x
    x = 516,745.40/878.90
  6. Step 6: Final answer
    x = 587.95

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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.