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Finding the Fourth Proportional to 999.12, 1,378.79 and 557.00

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Solution

The fourth proportional to 999.12, 1,378.79 and 557.00 is: 768.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.12 : 1,378.79 = 557.00 : x
  2. Step 2: Convert to fraction form
    999.12/1,378.79 = 557.00/x
  3. Step 3: Cross multiply
    999.12x = 1,378.79 × 557.00
  4. Step 4: Simplify right side
    999.12x = 767,983.61
  5. Step 5: Solve for x
    x = 767,983.61/999.12
  6. Step 6: Final answer
    x = 768.66

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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.