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Finding the Third Proportional to 418 and 639.50

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Solution

The third proportional to 418 and 639.50 is: 978.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    418 : 639.50 = 639.50 : x
  2. Step 2: Convert to fraction form
    418/639.50 = 639.50/x
  3. Step 3: Cross multiply
    418x = 639.50 × 639.50
  4. Step 4: Simplify right side
    418x = 408,960.25
  5. Step 5: Solve for x
    x = 408,960.25/418
  6. Step 6: Final answer
    x = 978.37

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These problems maintain the same ratio (1.53) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.