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Finding the Fourth Proportional to 999.30, 1,379.06 and 557.21

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Solution

The fourth proportional to 999.30, 1,379.06 and 557.21 is: 768.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.30 : 1,379.06 = 557.21 : x
  2. Step 2: Convert to fraction form
    999.30/1,379.06 = 557.21/x
  3. Step 3: Cross multiply
    999.30x = 1,379.06 × 557.21
  4. Step 4: Simplify right side
    999.30x = 768,416.34
  5. Step 5: Solve for x
    x = 768,416.34/999.30
  6. Step 6: Final answer
    x = 768.95

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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.