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Finding the Fourth Proportional to 819.60, 1,131.15 and 487.86

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Solution

The fourth proportional to 819.60, 1,131.15 and 487.86 is: 673.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.60 : 1,131.15 = 487.86 : x
  2. Step 2: Convert to fraction form
    819.60/1,131.15 = 487.86/x
  3. Step 3: Cross multiply
    819.60x = 1,131.15 × 487.86
  4. Step 4: Simplify right side
    819.60x = 551,842.84
  5. Step 5: Solve for x
    x = 551,842.84/819.60
  6. Step 6: Final answer
    x = 673.31

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.