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Finding the Third Proportional to 687.75 and 789.75

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Solution

The third proportional to 687.75 and 789.75 is: 906.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.75 : 789.75 = 789.75 : x
  2. Step 2: Convert to fraction form
    687.75/789.75 = 789.75/x
  3. Step 3: Cross multiply
    687.75x = 789.75 × 789.75
  4. Step 4: Simplify right side
    687.75x = 623,705.06
  5. Step 5: Solve for x
    x = 623,705.06/687.75
  6. Step 6: Final answer
    x = 906.88

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Why These Related Problems?

These problems maintain the same ratio (1.15) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.