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Finding the Third Proportional to 138.38 and 258.19

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Solution

The third proportional to 138.38 and 258.19 is: 481.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.38 : 258.19 = 258.19 : x
  2. Step 2: Convert to fraction form
    138.38/258.19 = 258.19/x
  3. Step 3: Cross multiply
    138.38x = 258.19 × 258.19
  4. Step 4: Simplify right side
    138.38x = 66,660.79
  5. Step 5: Solve for x
    x = 66,660.79/138.38
  6. Step 6: Final answer
    x = 481.74

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Why These Related Problems?

These problems maintain the same ratio (1.87) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.