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Finding the Fourth Proportional to 814.28, 1,221.08 and 320.61

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Solution

The fourth proportional to 814.28, 1,221.08 and 320.61 is: 480.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.28 : 1,221.08 = 320.61 : x
  2. Step 2: Convert to fraction form
    814.28/1,221.08 = 320.61/x
  3. Step 3: Cross multiply
    814.28x = 1,221.08 × 320.61
  4. Step 4: Simplify right side
    814.28x = 391,494.64
  5. Step 5: Solve for x
    x = 391,494.64/814.28
  6. Step 6: Final answer
    x = 480.78

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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.