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Finding the Fourth Proportional to 39.92, 55.11 and 28.31

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Solution

The fourth proportional to 39.92, 55.11 and 28.31 is: 39.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.92 : 55.11 = 28.31 : x
  2. Step 2: Convert to fraction form
    39.92/55.11 = 28.31/x
  3. Step 3: Cross multiply
    39.92x = 55.11 × 28.31
  4. Step 4: Simplify right side
    39.92x = 1,559.89
  5. Step 5: Solve for x
    x = 1,559.89/39.92
  6. Step 6: Final answer
    x = 39.07

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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.