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Finding the Fourth Proportional to 85.22, 127.68 and 81.20

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Solution

The fourth proportional to 85.22, 127.68 and 81.20 is: 121.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.22 : 127.68 = 81.20 : x
  2. Step 2: Convert to fraction form
    85.22/127.68 = 81.20/x
  3. Step 3: Cross multiply
    85.22x = 127.68 × 81.20
  4. Step 4: Simplify right side
    85.22x = 10,367.62
  5. Step 5: Solve for x
    x = 10,367.62/85.22
  6. Step 6: Final answer
    x = 121.66

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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.