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Finding the Fourth Proportional to 81.76, 112.81 and 54.18

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Solution

The fourth proportional to 81.76, 112.81 and 54.18 is: 74.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.76 : 112.81 = 54.18 : x
  2. Step 2: Convert to fraction form
    81.76/112.81 = 54.18/x
  3. Step 3: Cross multiply
    81.76x = 112.81 × 54.18
  4. Step 4: Simplify right side
    81.76x = 6,112.05
  5. Step 5: Solve for x
    x = 6,112.05/81.76
  6. Step 6: Final answer
    x = 74.76

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.