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Finding the Third Proportional to 639.14 and 1,380.80

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Solution

The third proportional to 639.14 and 1,380.80 is: 2,983.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.14 : 1,380.80 = 1,380.80 : x
  2. Step 2: Convert to fraction form
    639.14/1,380.80 = 1,380.80/x
  3. Step 3: Cross multiply
    639.14x = 1,380.80 × 1,380.80
  4. Step 4: Simplify right side
    639.14x = 1,906,600.01
  5. Step 5: Solve for x
    x = 1,906,600.01/639.14
  6. Step 6: Final answer
    x = 2,983.07

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Why These Related Problems?

These problems maintain the same ratio (2.16) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.