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Finding the Third Proportional to 678 and 742

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Solution

The third proportional to 678 and 742 is: 812.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    678 : 742 = 742 : x
  2. Step 2: Convert to fraction form
    678/742 = 742/x
  3. Step 3: Cross multiply
    678x = 742 × 742
  4. Step 4: Simplify right side
    678x = 550,564
  5. Step 5: Solve for x
    x = 550,564/678
  6. Step 6: Final answer
    x = 812.04

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Why These Related Problems?

These problems maintain the same ratio (1.09) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.