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Finding the Fourth Proportional to 138.47, 191.09 and 83.18

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Solution

The fourth proportional to 138.47, 191.09 and 83.18 is: 114.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.47 : 191.09 = 83.18 : x
  2. Step 2: Convert to fraction form
    138.47/191.09 = 83.18/x
  3. Step 3: Cross multiply
    138.47x = 191.09 × 83.18
  4. Step 4: Simplify right side
    138.47x = 15,893.49
  5. Step 5: Solve for x
    x = 15,893.49/138.47
  6. Step 6: Final answer
    x = 114.78

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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.