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Finding the Third Proportional to 20.39 and 40.15

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Solution

The third proportional to 20.39 and 40.15 is: 79.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.39 : 40.15 = 40.15 : x
  2. Step 2: Convert to fraction form
    20.39/40.15 = 40.15/x
  3. Step 3: Cross multiply
    20.39x = 40.15 × 40.15
  4. Step 4: Simplify right side
    20.39x = 1,611.90
  5. Step 5: Solve for x
    x = 1,611.90/20.39
  6. Step 6: Final answer
    x = 79.05

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Why These Related Problems?

These problems maintain the same ratio (1.97) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.