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Finding the Fourth Proportional to 54.36, 81.39 and 39.15

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Solution

The fourth proportional to 54.36, 81.39 and 39.15 is: 58.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.36 : 81.39 = 39.15 : x
  2. Step 2: Convert to fraction form
    54.36/81.39 = 39.15/x
  3. Step 3: Cross multiply
    54.36x = 81.39 × 39.15
  4. Step 4: Simplify right side
    54.36x = 3,186.42
  5. Step 5: Solve for x
    x = 3,186.42/54.36
  6. Step 6: Final answer
    x = 58.62

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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.