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Finding the Third Proportional to 639.88 and 978.19

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Solution

The third proportional to 639.88 and 978.19 is: 1,495.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.88 : 978.19 = 978.19 : x
  2. Step 2: Convert to fraction form
    639.88/978.19 = 978.19/x
  3. Step 3: Cross multiply
    639.88x = 978.19 × 978.19
  4. Step 4: Simplify right side
    639.88x = 956,850.79
  5. Step 5: Solve for x
    x = 956,850.79/639.88
  6. Step 6: Final answer
    x = 1,495.37

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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.