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Finding the Third Proportional to 6.40 and 13.78

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Solution

The third proportional to 6.40 and 13.78 is: 29.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.40 : 13.78 = 13.78 : x
  2. Step 2: Convert to fraction form
    6.40/13.78 = 13.78/x
  3. Step 3: Cross multiply
    6.40x = 13.78 × 13.78
  4. Step 4: Simplify right side
    6.40x = 189.92
  5. Step 5: Solve for x
    x = 189.92/6.40
  6. Step 6: Final answer
    x = 29.68

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Why These Related Problems?

These problems maintain the same ratio (2.15) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.