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Finding the Third Proportional to 408.09 and 679.78

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Solution

The third proportional to 408.09 and 679.78 is: 1,132.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.09 : 679.78 = 679.78 : x
  2. Step 2: Convert to fraction form
    408.09/679.78 = 679.78/x
  3. Step 3: Cross multiply
    408.09x = 679.78 × 679.78
  4. Step 4: Simplify right side
    408.09x = 462,102.55
  5. Step 5: Solve for x
    x = 462,102.55/408.09
  6. Step 6: Final answer
    x = 1,132.34

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Why These Related Problems?

These problems maintain the same ratio (1.67) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.