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Finding the Fourth Proportional to 54.38, 81.56 and 13.80

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Solution

The fourth proportional to 54.38, 81.56 and 13.80 is: 20.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.38 : 81.56 = 13.80 : x
  2. Step 2: Convert to fraction form
    54.38/81.56 = 13.80/x
  3. Step 3: Cross multiply
    54.38x = 81.56 × 13.80
  4. Step 4: Simplify right side
    54.38x = 1,125.12
  5. Step 5: Solve for x
    x = 1,125.12/54.38
  6. Step 6: Final answer
    x = 20.69

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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.