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Finding the Third Proportional to 20.87 and 40.80

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Solution

The third proportional to 20.87 and 40.80 is: 79.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.87 : 40.80 = 40.80 : x
  2. Step 2: Convert to fraction form
    20.87/40.80 = 40.80/x
  3. Step 3: Cross multiply
    20.87x = 40.80 × 40.80
  4. Step 4: Simplify right side
    20.87x = 1,665.02
  5. Step 5: Solve for x
    x = 1,665.02/20.87
  6. Step 6: Final answer
    x = 79.78

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Why These Related Problems?

These problems maintain the same ratio (1.96) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.