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Finding the Fourth Proportional to 13.78, 20.72 and 12.30

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Solution

The fourth proportional to 13.78, 20.72 and 12.30 is: 18.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.78 : 20.72 = 12.30 : x
  2. Step 2: Convert to fraction form
    13.78/20.72 = 12.30/x
  3. Step 3: Cross multiply
    13.78x = 20.72 × 12.30
  4. Step 4: Simplify right side
    13.78x = 254.86
  5. Step 5: Solve for x
    x = 254.86/13.78
  6. Step 6: Final answer
    x = 18.49

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.