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Finding the Third Proportional to 3,940 and 7,780

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Solution

The third proportional to 3,940 and 7,780 is: 15,362.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,940 : 7,780 = 7,780 : x
  2. Step 2: Convert to fraction form
    3,940/7,780 = 7,780/x
  3. Step 3: Cross multiply
    3,940x = 7,780 × 7,780
  4. Step 4: Simplify right side
    3,940x = 60,528,400
  5. Step 5: Solve for x
    x = 60,528,400/3,940
  6. Step 6: Final answer
    x = 15,362.54

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Why These Related Problems?

These problems maintain the same ratio (1.97) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.