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Finding the Fourth Proportional to 814.80, 1,221.17 and 381

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Solution

The fourth proportional to 814.80, 1,221.17 and 381 is: 571.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.80 : 1,221.17 = 381 : x
  2. Step 2: Convert to fraction form
    814.80/1,221.17 = 381/x
  3. Step 3: Cross multiply
    814.80x = 1,221.17 × 381
  4. Step 4: Simplify right side
    814.80x = 465,263.87
  5. Step 5: Solve for x
    x = 465,263.87/814.80
  6. Step 6: Final answer
    x = 571.02

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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.