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Finding the Third Proportional to 138.38 and 211.78

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Solution

The third proportional to 138.38 and 211.78 is: 324.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.38 : 211.78 = 211.78 : x
  2. Step 2: Convert to fraction form
    138.38/211.78 = 211.78/x
  3. Step 3: Cross multiply
    138.38x = 211.78 × 211.78
  4. Step 4: Simplify right side
    138.38x = 44,851.30
  5. Step 5: Solve for x
    x = 44,851.30/138.38
  6. Step 6: Final answer
    x = 324.13

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Why These Related Problems?

These problems maintain the same ratio (1.53) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.