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Finding the Fourth Proportional to 999.50, 1,379.28 and 557.40

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Solution

The fourth proportional to 999.50, 1,379.28 and 557.40 is: 769.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.50 : 1,379.28 = 557.40 : x
  2. Step 2: Convert to fraction form
    999.50/1,379.28 = 557.40/x
  3. Step 3: Cross multiply
    999.50x = 1,379.28 × 557.40
  4. Step 4: Simplify right side
    999.50x = 768,810.67
  5. Step 5: Solve for x
    x = 768,810.67/999.50
  6. Step 6: Final answer
    x = 769.20

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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.