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Finding the Fourth Proportional to 14.78, 20.40 and 12.38

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Solution

The fourth proportional to 14.78, 20.40 and 12.38 is: 17.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    14.78 : 20.40 = 12.38 : x
  2. Step 2: Convert to fraction form
    14.78/20.40 = 12.38/x
  3. Step 3: Cross multiply
    14.78x = 20.40 × 12.38
  4. Step 4: Simplify right side
    14.78x = 252.55
  5. Step 5: Solve for x
    x = 252.55/14.78
  6. Step 6: Final answer
    x = 17.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.