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Finding the Fourth Proportional to 878.16, 1,317.20 and 391.22

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Solution

The fourth proportional to 878.16, 1,317.20 and 391.22 is: 586.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.16 : 1,317.20 = 391.22 : x
  2. Step 2: Convert to fraction form
    878.16/1,317.20 = 391.22/x
  3. Step 3: Cross multiply
    878.16x = 1,317.20 × 391.22
  4. Step 4: Simplify right side
    878.16x = 515,306.44
  5. Step 5: Solve for x
    x = 515,306.44/878.16
  6. Step 6: Final answer
    x = 586.80

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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.