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Finding the Fourth Proportional to 819.28, 1,228.92 and 386.74

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Solution

The fourth proportional to 819.28, 1,228.92 and 386.74 is: 580.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.28 : 1,228.92 = 386.74 : x
  2. Step 2: Convert to fraction form
    819.28/1,228.92 = 386.74/x
  3. Step 3: Cross multiply
    819.28x = 1,228.92 × 386.74
  4. Step 4: Simplify right side
    819.28x = 475,272.52
  5. Step 5: Solve for x
    x = 475,272.52/819.28
  6. Step 6: Final answer
    x = 580.11

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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.