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Finding the Fourth Proportional to 13.78, 20.75 and 12.28

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Solution

The fourth proportional to 13.78, 20.75 and 12.28 is: 18.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.78 : 20.75 = 12.28 : x
  2. Step 2: Convert to fraction form
    13.78/20.75 = 12.28/x
  3. Step 3: Cross multiply
    13.78x = 20.75 × 12.28
  4. Step 4: Simplify right side
    13.78x = 254.81
  5. Step 5: Solve for x
    x = 254.81/13.78
  6. Step 6: Final answer
    x = 18.49

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.