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Finding the Fourth Proportional to 54.31, 81.39 and 42.12

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Solution

The fourth proportional to 54.31, 81.39 and 42.12 is: 63.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.31 : 81.39 = 42.12 : x
  2. Step 2: Convert to fraction form
    54.31/81.39 = 42.12/x
  3. Step 3: Cross multiply
    54.31x = 81.39 × 42.12
  4. Step 4: Simplify right side
    54.31x = 3,428.15
  5. Step 5: Solve for x
    x = 3,428.15/54.31
  6. Step 6: Final answer
    x = 63.12

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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.