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Finding the Third Proportional to 8,720 and 12,690

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Solution

The third proportional to 8,720 and 12,690 is: 18,467.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,720 : 12,690 = 12,690 : x
  2. Step 2: Convert to fraction form
    8,720/12,690 = 12,690/x
  3. Step 3: Cross multiply
    8,720x = 12,690 × 12,690
  4. Step 4: Simplify right side
    8,720x = 161,036,100
  5. Step 5: Solve for x
    x = 161,036,100/8,720
  6. Step 6: Final answer
    x = 18,467.44

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Why These Related Problems?

These problems maintain the same ratio (1.46) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.