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Finding the Fourth Proportional to 397.88, 551.42 and 391.80

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Solution

The fourth proportional to 397.88, 551.42 and 391.80 is: 543.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    397.88 : 551.42 = 391.80 : x
  2. Step 2: Convert to fraction form
    397.88/551.42 = 391.80/x
  3. Step 3: Cross multiply
    397.88x = 551.42 × 391.80
  4. Step 4: Simplify right side
    397.88x = 216,044.40
  5. Step 5: Solve for x
    x = 216,044.40/397.88
  6. Step 6: Final answer
    x = 543.00

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.