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Finding the Third Proportional to 3,420 and 7,890

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Solution

The third proportional to 3,420 and 7,890 is: 18,202.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,420 : 7,890 = 7,890 : x
  2. Step 2: Convert to fraction form
    3,420/7,890 = 7,890/x
  3. Step 3: Cross multiply
    3,420x = 7,890 × 7,890
  4. Step 4: Simplify right side
    3,420x = 62,252,100
  5. Step 5: Solve for x
    x = 62,252,100/3,420
  6. Step 6: Final answer
    x = 18,202.37

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Why These Related Problems?

These problems maintain the same ratio (2.31) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.