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Finding the Fourth Proportional to 39.96, 55.11 and 30.61

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Solution

The fourth proportional to 39.96, 55.11 and 30.61 is: 42.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.96 : 55.11 = 30.61 : x
  2. Step 2: Convert to fraction form
    39.96/55.11 = 30.61/x
  3. Step 3: Cross multiply
    39.96x = 55.11 × 30.61
  4. Step 4: Simplify right side
    39.96x = 1,687.10
  5. Step 5: Solve for x
    x = 1,687.10/39.96
  6. Step 6: Final answer
    x = 42.22

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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.