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Finding the Fourth Proportional to 138.17, 206.84 and 83.90

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Solution

The fourth proportional to 138.17, 206.84 and 83.90 is: 125.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.17 : 206.84 = 83.90 : x
  2. Step 2: Convert to fraction form
    138.17/206.84 = 83.90/x
  3. Step 3: Cross multiply
    138.17x = 206.84 × 83.90
  4. Step 4: Simplify right side
    138.17x = 17,353.88
  5. Step 5: Solve for x
    x = 17,353.88/138.17
  6. Step 6: Final answer
    x = 125.60

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.