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Finding the Fourth Proportional to 87.11, 120.06 and 74.78

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Solution

The fourth proportional to 87.11, 120.06 and 74.78 is: 103.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.11 : 120.06 = 74.78 : x
  2. Step 2: Convert to fraction form
    87.11/120.06 = 74.78/x
  3. Step 3: Cross multiply
    87.11x = 120.06 × 74.78
  4. Step 4: Simplify right side
    87.11x = 8,978.09
  5. Step 5: Solve for x
    x = 8,978.09/87.11
  6. Step 6: Final answer
    x = 103.07

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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.