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Finding the Fourth Proportional to 819.90, 1,228.53 and 408.42

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Solution

The fourth proportional to 819.90, 1,228.53 and 408.42 is: 611.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.90 : 1,228.53 = 408.42 : x
  2. Step 2: Convert to fraction form
    819.90/1,228.53 = 408.42/x
  3. Step 3: Cross multiply
    819.90x = 1,228.53 × 408.42
  4. Step 4: Simplify right side
    819.90x = 501,756.22
  5. Step 5: Solve for x
    x = 501,756.22/819.90
  6. Step 6: Final answer
    x = 611.97

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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.