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Finding the Fourth Proportional to 39.86, 54.90 and 28.92

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Solution

The fourth proportional to 39.86, 54.90 and 28.92 is: 39.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.86 : 54.90 = 28.92 : x
  2. Step 2: Convert to fraction form
    39.86/54.90 = 28.92/x
  3. Step 3: Cross multiply
    39.86x = 54.90 × 28.92
  4. Step 4: Simplify right side
    39.86x = 1,587.71
  5. Step 5: Solve for x
    x = 1,587.71/39.86
  6. Step 6: Final answer
    x = 39.83

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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.