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Finding the Fourth Proportional to 91.06, 125.38 and 81.20

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Solution

The fourth proportional to 91.06, 125.38 and 81.20 is: 111.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.06 : 125.38 = 81.20 : x
  2. Step 2: Convert to fraction form
    91.06/125.38 = 81.20/x
  3. Step 3: Cross multiply
    91.06x = 125.38 × 81.20
  4. Step 4: Simplify right side
    91.06x = 10,181.27
  5. Step 5: Solve for x
    x = 10,181.27/91.06
  6. Step 6: Final answer
    x = 111.81

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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.