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Finding the Third Proportional to 138.38 and 221.69

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Solution

The third proportional to 138.38 and 221.69 is: 355.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.38 : 221.69 = 221.69 : x
  2. Step 2: Convert to fraction form
    138.38/221.69 = 221.69/x
  3. Step 3: Cross multiply
    138.38x = 221.69 × 221.69
  4. Step 4: Simplify right side
    138.38x = 49,145.35
  5. Step 5: Solve for x
    x = 49,145.35/138.38
  6. Step 6: Final answer
    x = 355.16

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Why These Related Problems?

These problems maintain the same ratio (1.60) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.