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Finding the Third Proportional to 639 and 1,138.13

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Solution

The third proportional to 639 and 1,138.13 is: 2,027.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    639 : 1,138.13 = 1,138.13 : x
  2. Step 2: Convert to fraction form
    639/1,138.13 = 1,138.13/x
  3. Step 3: Cross multiply
    639x = 1,138.13 × 1,138.13
  4. Step 4: Simplify right side
    639x = 1,295,328.52
  5. Step 5: Solve for x
    x = 1,295,328.52/639
  6. Step 6: Final answer
    x = 2,027.12

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Why These Related Problems?

These problems maintain the same ratio (1.78) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.