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Finding the Fourth Proportional to 80.66, 111.86 and 77.65

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Solution

The fourth proportional to 80.66, 111.86 and 77.65 is: 107.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.66 : 111.86 = 77.65 : x
  2. Step 2: Convert to fraction form
    80.66/111.86 = 77.65/x
  3. Step 3: Cross multiply
    80.66x = 111.86 × 77.65
  4. Step 4: Simplify right side
    80.66x = 8,685.93
  5. Step 5: Solve for x
    x = 8,685.93/80.66
  6. Step 6: Final answer
    x = 107.69

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.