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Finding the Fourth Proportional to 878.30, 1,317.86 and 391.30

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Solution

The fourth proportional to 878.30, 1,317.86 and 391.30 is: 587.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.30 : 1,317.86 = 391.30 : x
  2. Step 2: Convert to fraction form
    878.30/1,317.86 = 391.30/x
  3. Step 3: Cross multiply
    878.30x = 1,317.86 × 391.30
  4. Step 4: Simplify right side
    878.30x = 515,678.62
  5. Step 5: Solve for x
    x = 515,678.62/878.30
  6. Step 6: Final answer
    x = 587.13

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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.