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Finding the Third Proportional to 12 and 15

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Solution

The third proportional to 12 and 15 is: 18.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    12 : 15 = 15 : x
  2. Step 2: Convert to fraction form
    12/15 = 15/x
  3. Step 3: Cross multiply
    12x = 15 × 15
  4. Step 4: Simplify right side
    12x = 225
  5. Step 5: Solve for x
    x = 225/12
  6. Step 6: Final answer
    x = 18.75

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Why These Related Problems?

These problems maintain the same ratio (1.25) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.