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Finding the Fourth Proportional to 138.90, 191.66 and 107.79

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Solution

The fourth proportional to 138.90, 191.66 and 107.79 is: 148.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.90 : 191.66 = 107.79 : x
  2. Step 2: Convert to fraction form
    138.90/191.66 = 107.79/x
  3. Step 3: Cross multiply
    138.90x = 191.66 × 107.79
  4. Step 4: Simplify right side
    138.90x = 20,659.03
  5. Step 5: Solve for x
    x = 20,659.03/138.90
  6. Step 6: Final answer
    x = 148.73

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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.