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Finding the Third Proportional to 12,990 and 20,919

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Solution

The third proportional to 12,990 and 20,919 is: 33,687.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    12,990 : 20,919 = 20,919 : x
  2. Step 2: Convert to fraction form
    12,990/20,919 = 20,919/x
  3. Step 3: Cross multiply
    12,990x = 20,919 × 20,919
  4. Step 4: Simplify right side
    12,990x = 437,604,561
  5. Step 5: Solve for x
    x = 437,604,561/12,990
  6. Step 6: Final answer
    x = 33,687.80

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.61) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.