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Finding the Fourth Proportional to 398.78, 550.38 and 251.30

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Solution

The fourth proportional to 398.78, 550.38 and 251.30 is: 346.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.78 : 550.38 = 251.30 : x
  2. Step 2: Convert to fraction form
    398.78/550.38 = 251.30/x
  3. Step 3: Cross multiply
    398.78x = 550.38 × 251.30
  4. Step 4: Simplify right side
    398.78x = 138,307.74
  5. Step 5: Solve for x
    x = 138,307.74/398.78
  6. Step 6: Final answer
    x = 346.83

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.