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Finding the Fourth Proportional to 138.87, 191.63 and 83.65

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Solution

The fourth proportional to 138.87, 191.63 and 83.65 is: 115.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.87 : 191.63 = 83.65 : x
  2. Step 2: Convert to fraction form
    138.87/191.63 = 83.65/x
  3. Step 3: Cross multiply
    138.87x = 191.63 × 83.65
  4. Step 4: Simplify right side
    138.87x = 16,029.85
  5. Step 5: Solve for x
    x = 16,029.85/138.87
  6. Step 6: Final answer
    x = 115.43

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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.