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Finding the Third Proportional to 8.72 and 12.80

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Solution

The third proportional to 8.72 and 12.80 is: 18.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.72 : 12.80 = 12.80 : x
  2. Step 2: Convert to fraction form
    8.72/12.80 = 12.80/x
  3. Step 3: Cross multiply
    8.72x = 12.80 × 12.80
  4. Step 4: Simplify right side
    8.72x = 163.76
  5. Step 5: Solve for x
    x = 163.76/8.72
  6. Step 6: Final answer
    x = 18.78

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Why These Related Problems?

These problems maintain the same ratio (1.47) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.