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Finding the Fourth Proportional to 819.24, 1,229.40 and 386.43

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Solution

The fourth proportional to 819.24, 1,229.40 and 386.43 is: 579.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.24 : 1,229.40 = 386.43 : x
  2. Step 2: Convert to fraction form
    819.24/1,229.40 = 386.43/x
  3. Step 3: Cross multiply
    819.24x = 1,229.40 × 386.43
  4. Step 4: Simplify right side
    819.24x = 475,077.04
  5. Step 5: Solve for x
    x = 475,077.04/819.24
  6. Step 6: Final answer
    x = 579.90

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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.