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Finding the Fourth Proportional to 80.78, 110.89 and 69.71

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Solution

The fourth proportional to 80.78, 110.89 and 69.71 is: 95.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.78 : 110.89 = 69.71 : x
  2. Step 2: Convert to fraction form
    80.78/110.89 = 69.71/x
  3. Step 3: Cross multiply
    80.78x = 110.89 × 69.71
  4. Step 4: Simplify right side
    80.78x = 7,729.67
  5. Step 5: Solve for x
    x = 7,729.67/80.78
  6. Step 6: Final answer
    x = 95.69

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.