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Finding the Third Proportional to 639.75 and 705.75

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Solution

The third proportional to 639.75 and 705.75 is: 778.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.75 : 705.75 = 705.75 : x
  2. Step 2: Convert to fraction form
    639.75/705.75 = 705.75/x
  3. Step 3: Cross multiply
    639.75x = 705.75 × 705.75
  4. Step 4: Simplify right side
    639.75x = 498,083.06
  5. Step 5: Solve for x
    x = 498,083.06/639.75
  6. Step 6: Final answer
    x = 778.56

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These problems maintain the same ratio (1.10) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.