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Finding the Third Proportional to 409.88 and 639.09

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Solution

The third proportional to 409.88 and 639.09 is: 996.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    409.88 : 639.09 = 639.09 : x
  2. Step 2: Convert to fraction form
    409.88/639.09 = 639.09/x
  3. Step 3: Cross multiply
    409.88x = 639.09 × 639.09
  4. Step 4: Simplify right side
    409.88x = 408,440.82
  5. Step 5: Solve for x
    x = 408,440.82/409.88
  6. Step 6: Final answer
    x = 996.50

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Why These Related Problems?

These problems maintain the same ratio (1.56) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.