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Finding the Fourth Proportional to 91.05, 135.87 and 80.79

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Solution

The fourth proportional to 91.05, 135.87 and 80.79 is: 120.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.05 : 135.87 = 80.79 : x
  2. Step 2: Convert to fraction form
    91.05/135.87 = 80.79/x
  3. Step 3: Cross multiply
    91.05x = 135.87 × 80.79
  4. Step 4: Simplify right side
    91.05x = 10,976.94
  5. Step 5: Solve for x
    x = 10,976.94/91.05
  6. Step 6: Final answer
    x = 120.56

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.