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Finding the Fourth Proportional to 138.85, 191.62 and 76.69

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Solution

The fourth proportional to 138.85, 191.62 and 76.69 is: 105.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.85 : 191.62 = 76.69 : x
  2. Step 2: Convert to fraction form
    138.85/191.62 = 76.69/x
  3. Step 3: Cross multiply
    138.85x = 191.62 × 76.69
  4. Step 4: Simplify right side
    138.85x = 14,694.67
  5. Step 5: Solve for x
    x = 14,694.67/138.85
  6. Step 6: Final answer
    x = 105.83

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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.