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Finding the Fourth Proportional to 408.20, 611.01 and 261.76

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Solution

The fourth proportional to 408.20, 611.01 and 261.76 is: 391.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.20 : 611.01 = 261.76 : x
  2. Step 2: Convert to fraction form
    408.20/611.01 = 261.76/x
  3. Step 3: Cross multiply
    408.20x = 611.01 × 261.76
  4. Step 4: Simplify right side
    408.20x = 159,937.10
  5. Step 5: Solve for x
    x = 159,937.10/408.20
  6. Step 6: Final answer
    x = 391.81

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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.