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Finding the Third Proportional to 381.38 and 688.69

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Solution

The third proportional to 381.38 and 688.69 is: 1,243.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    381.38 : 688.69 = 688.69 : x
  2. Step 2: Convert to fraction form
    381.38/688.69 = 688.69/x
  3. Step 3: Cross multiply
    381.38x = 688.69 × 688.69
  4. Step 4: Simplify right side
    381.38x = 474,290.47
  5. Step 5: Solve for x
    x = 474,290.47/381.38
  6. Step 6: Final answer
    x = 1,243.63

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Why These Related Problems?

These problems maintain the same ratio (1.81) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.