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Finding the Third Proportional to 381 and 399

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Solution

The third proportional to 381 and 399 is: 417.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    381 : 399 = 399 : x
  2. Step 2: Convert to fraction form
    381/399 = 399/x
  3. Step 3: Cross multiply
    381x = 399 × 399
  4. Step 4: Simplify right side
    381x = 159,201
  5. Step 5: Solve for x
    x = 159,201/381
  6. Step 6: Final answer
    x = 417.85

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Why These Related Problems?

These problems maintain the same ratio (1.05) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.