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Finding the Fourth Proportional to 138.68, 191.42 and 83.42

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Solution

The fourth proportional to 138.68, 191.42 and 83.42 is: 115.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.68 : 191.42 = 83.42 : x
  2. Step 2: Convert to fraction form
    138.68/191.42 = 83.42/x
  3. Step 3: Cross multiply
    138.68x = 191.42 × 83.42
  4. Step 4: Simplify right side
    138.68x = 15,968.94
  5. Step 5: Solve for x
    x = 15,968.94/138.68
  6. Step 6: Final answer
    x = 115.15

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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.