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Finding the Fourth Proportional to 609.11, 840.85 and 399.30

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Solution

The fourth proportional to 609.11, 840.85 and 399.30 is: 551.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    609.11 : 840.85 = 399.30 : x
  2. Step 2: Convert to fraction form
    609.11/840.85 = 399.30/x
  3. Step 3: Cross multiply
    609.11x = 840.85 × 399.30
  4. Step 4: Simplify right side
    609.11x = 335,751.41
  5. Step 5: Solve for x
    x = 335,751.41/609.11
  6. Step 6: Final answer
    x = 551.22

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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.