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Finding the Fourth Proportional to 138.12, 206.22 and 121.92

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Solution

The fourth proportional to 138.12, 206.22 and 121.92 is: 182.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.12 : 206.22 = 121.92 : x
  2. Step 2: Convert to fraction form
    138.12/206.22 = 121.92/x
  3. Step 3: Cross multiply
    138.12x = 206.22 × 121.92
  4. Step 4: Simplify right side
    138.12x = 25,142.34
  5. Step 5: Solve for x
    x = 25,142.34/138.12
  6. Step 6: Final answer
    x = 182.03

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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.