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Finding the Third Proportional to 12.89 and 19.99

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Solution

The third proportional to 12.89 and 19.99 is: 31.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.89 : 19.99 = 19.99 : x
  2. Step 2: Convert to fraction form
    12.89/19.99 = 19.99/x
  3. Step 3: Cross multiply
    12.89x = 19.99 × 19.99
  4. Step 4: Simplify right side
    12.89x = 399.69
  5. Step 5: Solve for x
    x = 399.69/12.89
  6. Step 6: Final answer
    x = 31.01

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Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.