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Finding the Third Proportional to 20 and 39

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Solution

The third proportional to 20 and 39 is: 76.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    20 : 39 = 39 : x
  2. Step 2: Convert to fraction form
    20/39 = 39/x
  3. Step 3: Cross multiply
    20x = 39 × 39
  4. Step 4: Simplify right side
    20x = 1,521
  5. Step 5: Solve for x
    x = 1,521/20
  6. Step 6: Final answer
    x = 76.05

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Why These Related Problems?

These problems maintain the same ratio (1.95) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.