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Finding the Third Proportional to 8,378 and 12,990

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Solution

The third proportional to 8,378 and 12,990 is: 20,140.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,378 : 12,990 = 12,990 : x
  2. Step 2: Convert to fraction form
    8,378/12,990 = 12,990/x
  3. Step 3: Cross multiply
    8,378x = 12,990 × 12,990
  4. Step 4: Simplify right side
    8,378x = 168,740,100
  5. Step 5: Solve for x
    x = 168,740,100/8,378
  6. Step 6: Final answer
    x = 20,140.86

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Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.