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Finding the Fourth Proportional to 89.81, 134.61 and 80.65

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Solution

The fourth proportional to 89.81, 134.61 and 80.65 is: 120.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.81 : 134.61 = 80.65 : x
  2. Step 2: Convert to fraction form
    89.81/134.61 = 80.65/x
  3. Step 3: Cross multiply
    89.81x = 134.61 × 80.65
  4. Step 4: Simplify right side
    89.81x = 10,855.86
  5. Step 5: Solve for x
    x = 10,855.86/89.81
  6. Step 6: Final answer
    x = 120.88

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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.