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Finding the Fourth Proportional to 54.39, 81.57 and 21.87

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Solution

The fourth proportional to 54.39, 81.57 and 21.87 is: 32.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.39 : 81.57 = 21.87 : x
  2. Step 2: Convert to fraction form
    54.39/81.57 = 21.87/x
  3. Step 3: Cross multiply
    54.39x = 81.57 × 21.87
  4. Step 4: Simplify right side
    54.39x = 1,783.42
  5. Step 5: Solve for x
    x = 1,783.42/54.39
  6. Step 6: Final answer
    x = 32.79

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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.