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Finding the Fourth Proportional to 91.09, 135.99 and 80.86

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Solution

The fourth proportional to 91.09, 135.99 and 80.86 is: 120.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.09 : 135.99 = 80.86 : x
  2. Step 2: Convert to fraction form
    91.09/135.99 = 80.86/x
  3. Step 3: Cross multiply
    91.09x = 135.99 × 80.86
  4. Step 4: Simplify right side
    91.09x = 10,996.15
  5. Step 5: Solve for x
    x = 10,996.15/91.09
  6. Step 6: Final answer
    x = 120.72

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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.