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Finding the Fourth Proportional to 999.99, 1,380 and 557.91

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Solution

The fourth proportional to 999.99, 1,380 and 557.91 is: 769.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.99 : 1,380 = 557.91 : x
  2. Step 2: Convert to fraction form
    999.99/1,380 = 557.91/x
  3. Step 3: Cross multiply
    999.99x = 1,380 × 557.91
  4. Step 4: Simplify right side
    999.99x = 769,915.80
  5. Step 5: Solve for x
    x = 769,915.80/999.99
  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.