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Finding the Fourth Proportional to 625.60, 938.40 and 420.31

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Solution

The fourth proportional to 625.60, 938.40 and 420.31 is: 630.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    625.60 : 938.40 = 420.31 : x
  2. Step 2: Convert to fraction form
    625.60/938.40 = 420.31/x
  3. Step 3: Cross multiply
    625.60x = 938.40 × 420.31
  4. Step 4: Simplify right side
    625.60x = 394,418.90
  5. Step 5: Solve for x
    x = 394,418.90/625.60
  6. Step 6: Final answer
    x = 630.47

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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.