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Finding the Third Proportional to 8,421 and 12,129

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Solution

The third proportional to 8,421 and 12,129 is: 17,469.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,421 : 12,129 = 12,129 : x
  2. Step 2: Convert to fraction form
    8,421/12,129 = 12,129/x
  3. Step 3: Cross multiply
    8,421x = 12,129 × 12,129
  4. Step 4: Simplify right side
    8,421x = 147,112,641
  5. Step 5: Solve for x
    x = 147,112,641/8,421
  6. Step 6: Final answer
    x = 17,469.74

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Why These Related Problems?

These problems maintain the same ratio (1.44) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.