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Finding the Fourth Proportional to 138.05, 207.31 and 113.91

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Solution

The fourth proportional to 138.05, 207.31 and 113.91 is: 171.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.05 : 207.31 = 113.91 : x
  2. Step 2: Convert to fraction form
    138.05/207.31 = 113.91/x
  3. Step 3: Cross multiply
    138.05x = 207.31 × 113.91
  4. Step 4: Simplify right side
    138.05x = 23,613.83
  5. Step 5: Solve for x
    x = 23,613.83/138.05
  6. Step 6: Final answer
    x = 171.05

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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.