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Finding the Third Proportional to 3.86 and 8.42

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Solution

The third proportional to 3.86 and 8.42 is: 18.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    3.86 : 8.42 = 8.42 : x
  2. Step 2: Convert to fraction form
    3.86/8.42 = 8.42/x
  3. Step 3: Cross multiply
    3.86x = 8.42 × 8.42
  4. Step 4: Simplify right side
    3.86x = 70.94
  5. Step 5: Solve for x
    x = 70.94/3.86
  6. Step 6: Final answer
    x = 18.40

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Why These Related Problems?

These problems maintain the same ratio (2.18) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.