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Finding the Fourth Proportional to 679.87, 938.21 and 385.20

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Solution

The fourth proportional to 679.87, 938.21 and 385.20 is: 531.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.87 : 938.21 = 385.20 : x
  2. Step 2: Convert to fraction form
    679.87/938.21 = 385.20/x
  3. Step 3: Cross multiply
    679.87x = 938.21 × 385.20
  4. Step 4: Simplify right side
    679.87x = 361,394.76
  5. Step 5: Solve for x
    x = 361,394.76/679.87
  6. Step 6: Final answer
    x = 531.56

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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.