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Finding the Third Proportional to 138.47 and 206.91

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Solution

The third proportional to 138.47 and 206.91 is: 309.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.47 : 206.91 = 206.91 : x
  2. Step 2: Convert to fraction form
    138.47/206.91 = 206.91/x
  3. Step 3: Cross multiply
    138.47x = 206.91 × 206.91
  4. Step 4: Simplify right side
    138.47x = 42,810.20
  5. Step 5: Solve for x
    x = 42,810.20/138.47
  6. Step 6: Final answer
    x = 309.17

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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.