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Finding the Fourth Proportional to 679.87, 938.39 and 385.31

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Solution

The fourth proportional to 679.87, 938.39 and 385.31 is: 531.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.87 : 938.39 = 385.31 : x
  2. Step 2: Convert to fraction form
    679.87/938.39 = 385.31/x
  3. Step 3: Cross multiply
    679.87x = 938.39 × 385.31
  4. Step 4: Simplify right side
    679.87x = 361,569.12
  5. Step 5: Solve for x
    x = 361,569.12/679.87
  6. Step 6: Final answer
    x = 531.82

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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.