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Finding the Fourth Proportional to 138.91, 208.61 and 74.83

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Solution

The fourth proportional to 138.91, 208.61 and 74.83 is: 112.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.91 : 208.61 = 74.83 : x
  2. Step 2: Convert to fraction form
    138.91/208.61 = 74.83/x
  3. Step 3: Cross multiply
    138.91x = 208.61 × 74.83
  4. Step 4: Simplify right side
    138.91x = 15,610.29
  5. Step 5: Solve for x
    x = 15,610.29/138.91
  6. Step 6: Final answer
    x = 112.38

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.