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Finding the Fourth Proportional to 878.88, 1,318.40 and 391.68

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Solution

The fourth proportional to 878.88, 1,318.40 and 391.68 is: 587.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.88 : 1,318.40 = 391.68 : x
  2. Step 2: Convert to fraction form
    878.88/1,318.40 = 391.68/x
  3. Step 3: Cross multiply
    878.88x = 1,318.40 × 391.68
  4. Step 4: Simplify right side
    878.88x = 516,390.91
  5. Step 5: Solve for x
    x = 516,390.91/878.88
  6. Step 6: Final answer
    x = 587.56

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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.