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Finding the Fourth Proportional to 999.98, 1,380 and 557.90

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Solution

The fourth proportional to 999.98, 1,380 and 557.90 is: 769.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.98 : 1,380 = 557.90 : x
  2. Step 2: Convert to fraction form
    999.98/1,380 = 557.90/x
  3. Step 3: Cross multiply
    999.98x = 1,380 × 557.90
  4. Step 4: Simplify right side
    999.98x = 769,905.45
  5. Step 5: Solve for x
    x = 769,905.45/999.98
  6. Step 6: Final answer
    x = 769.92

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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.