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Finding the Fourth Proportional to 609.20, 840.42 and 399.29

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Solution

The fourth proportional to 609.20, 840.42 and 399.29 is: 550.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    609.20 : 840.42 = 399.29 : x
  2. Step 2: Convert to fraction form
    609.20/840.42 = 399.29/x
  3. Step 3: Cross multiply
    609.20x = 840.42 × 399.29
  4. Step 4: Simplify right side
    609.20x = 335,573.40
  5. Step 5: Solve for x
    x = 335,573.40/609.20
  6. Step 6: Final answer
    x = 550.85

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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.