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Finding the Fourth Proportional to 819.45, 1,130.78 and 487.90

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Solution

The fourth proportional to 819.45, 1,130.78 and 487.90 is: 673.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.45 : 1,130.78 = 487.90 : x
  2. Step 2: Convert to fraction form
    819.45/1,130.78 = 487.90/x
  3. Step 3: Cross multiply
    819.45x = 1,130.78 × 487.90
  4. Step 4: Simplify right side
    819.45x = 551,707.56
  5. Step 5: Solve for x
    x = 551,707.56/819.45
  6. Step 6: Final answer
    x = 673.27

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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.