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Finding the Fourth Proportional to 91.09, 136.56 and 81.43

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Solution

The fourth proportional to 91.09, 136.56 and 81.43 is: 122.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.09 : 136.56 = 81.43 : x
  2. Step 2: Convert to fraction form
    91.09/136.56 = 81.43/x
  3. Step 3: Cross multiply
    91.09x = 136.56 × 81.43
  4. Step 4: Simplify right side
    91.09x = 11,120.08
  5. Step 5: Solve for x
    x = 11,120.08/91.09
  6. Step 6: Final answer
    x = 122.08

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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.