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Finding the Fourth Proportional to 138.75, 206.90 and 119.61

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Solution

The fourth proportional to 138.75, 206.90 and 119.61 is: 178.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.75 : 206.90 = 119.61 : x
  2. Step 2: Convert to fraction form
    138.75/206.90 = 119.61/x
  3. Step 3: Cross multiply
    138.75x = 206.90 × 119.61
  4. Step 4: Simplify right side
    138.75x = 24,747.31
  5. Step 5: Solve for x
    x = 24,747.31/138.75
  6. Step 6: Final answer
    x = 178.36

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.