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Finding the Fourth Proportional to 819.68, 1,229.65 and 408.74

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Solution

The fourth proportional to 819.68, 1,229.65 and 408.74 is: 613.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.68 : 1,229.65 = 408.74 : x
  2. Step 2: Convert to fraction form
    819.68/1,229.65 = 408.74/x
  3. Step 3: Cross multiply
    819.68x = 1,229.65 × 408.74
  4. Step 4: Simplify right side
    819.68x = 502,599.97
  5. Step 5: Solve for x
    x = 502,599.97/819.68
  6. Step 6: Final answer
    x = 613.17

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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.