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Finding the Fourth Proportional to 8.78, 13.09 and 8.55

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Solution

The fourth proportional to 8.78, 13.09 and 8.55 is: 12.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.78 : 13.09 = 8.55 : x
  2. Step 2: Convert to fraction form
    8.78/13.09 = 8.55/x
  3. Step 3: Cross multiply
    8.78x = 13.09 × 8.55
  4. Step 4: Simplify right side
    8.78x = 111.97
  5. Step 5: Solve for x
    x = 111.97/8.78
  6. Step 6: Final answer
    x = 12.75

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.