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Finding the Fourth Proportional to 624.40, 861.32 and 391.12

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Solution

The fourth proportional to 624.40, 861.32 and 391.12 is: 539.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    624.40 : 861.32 = 391.12 : x
  2. Step 2: Convert to fraction form
    624.40/861.32 = 391.12/x
  3. Step 3: Cross multiply
    624.40x = 861.32 × 391.12
  4. Step 4: Simplify right side
    624.40x = 336,879.48
  5. Step 5: Solve for x
    x = 336,879.48/624.40
  6. Step 6: Final answer
    x = 539.53

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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.