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Finding the Third Proportional to 8.78 and 20.40

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Solution

The third proportional to 8.78 and 20.40 is: 47.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.78 : 20.40 = 20.40 : x
  2. Step 2: Convert to fraction form
    8.78/20.40 = 20.40/x
  3. Step 3: Cross multiply
    8.78x = 20.40 × 20.40
  4. Step 4: Simplify right side
    8.78x = 416.26
  5. Step 5: Solve for x
    x = 416.26/8.78
  6. Step 6: Final answer
    x = 47.42

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Why These Related Problems?

These problems maintain the same ratio (2.32) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.