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Finding the Fourth Proportional to 871, 1,306.20 and 408.70

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Solution

The fourth proportional to 871, 1,306.20 and 408.70 is: 612.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    871 : 1,306.20 = 408.70 : x
  2. Step 2: Convert to fraction form
    871/1,306.20 = 408.70/x
  3. Step 3: Cross multiply
    871x = 1,306.20 × 408.70
  4. Step 4: Simplify right side
    871x = 533,843.94
  5. Step 5: Solve for x
    x = 533,843.94/871
  6. Step 6: Final answer
    x = 612.91

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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.