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Finding the Fourth Proportional to 819.90, 1,131.60 and 558

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Solution

The fourth proportional to 819.90, 1,131.60 and 558 is: 770.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.90 : 1,131.60 = 558 : x
  2. Step 2: Convert to fraction form
    819.90/1,131.60 = 558/x
  3. Step 3: Cross multiply
    819.90x = 1,131.60 × 558
  4. Step 4: Simplify right side
    819.90x = 631,432.80
  5. Step 5: Solve for x
    x = 631,432.80/819.90
  6. Step 6: Final answer
    x = 770.13

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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.