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Finding the Fourth Proportional to 641.87, 886.20 and 405.91

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Solution

The fourth proportional to 641.87, 886.20 and 405.91 is: 560.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.87 : 886.20 = 405.91 : x
  2. Step 2: Convert to fraction form
    641.87/886.20 = 405.91/x
  3. Step 3: Cross multiply
    641.87x = 886.20 × 405.91
  4. Step 4: Simplify right side
    641.87x = 359,717.44
  5. Step 5: Solve for x
    x = 359,717.44/641.87
  6. Step 6: Final answer
    x = 560.42

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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.