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Finding the Fourth Proportional to 81.36, 121.82 and 40.68

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Solution

The fourth proportional to 81.36, 121.82 and 40.68 is: 60.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.36 : 121.82 = 40.68 : x
  2. Step 2: Convert to fraction form
    81.36/121.82 = 40.68/x
  3. Step 3: Cross multiply
    81.36x = 121.82 × 40.68
  4. Step 4: Simplify right side
    81.36x = 4,955.64
  5. Step 5: Solve for x
    x = 4,955.64/81.36
  6. Step 6: Final answer
    x = 60.91

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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.