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Finding the Fourth Proportional to 54.12, 81.12 and 21.57

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Solution

The fourth proportional to 54.12, 81.12 and 21.57 is: 32.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.12 : 81.12 = 21.57 : x
  2. Step 2: Convert to fraction form
    54.12/81.12 = 21.57/x
  3. Step 3: Cross multiply
    54.12x = 81.12 × 21.57
  4. Step 4: Simplify right side
    54.12x = 1,749.96
  5. Step 5: Solve for x
    x = 1,749.96/54.12
  6. Step 6: Final answer
    x = 32.34

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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.