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Finding the Fourth Proportional to 138.89, 209.17 and 121.07

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Solution

The fourth proportional to 138.89, 209.17 and 121.07 is: 182.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.89 : 209.17 = 121.07 : x
  2. Step 2: Convert to fraction form
    138.89/209.17 = 121.07/x
  3. Step 3: Cross multiply
    138.89x = 209.17 × 121.07
  4. Step 4: Simplify right side
    138.89x = 25,323.61
  5. Step 5: Solve for x
    x = 25,323.61/138.89
  6. Step 6: Final answer
    x = 182.33

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.