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Finding the Third Proportional to 18 and 19.69

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Solution

The third proportional to 18 and 19.69 is: 21.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    18 : 19.69 = 19.69 : x
  2. Step 2: Convert to fraction form
    18/19.69 = 19.69/x
  3. Step 3: Cross multiply
    18x = 19.69 × 19.69
  4. Step 4: Simplify right side
    18x = 387.60
  5. Step 5: Solve for x
    x = 387.60/18
  6. Step 6: Final answer
    x = 21.53

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Why These Related Problems?

These problems maintain the same ratio (1.09) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.