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Finding the Fourth Proportional to 77.78, 107.91 and 77.11

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Solution

The fourth proportional to 77.78, 107.91 and 77.11 is: 106.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.78 : 107.91 = 77.11 : x
  2. Step 2: Convert to fraction form
    77.78/107.91 = 77.11/x
  3. Step 3: Cross multiply
    77.78x = 107.91 × 77.11
  4. Step 4: Simplify right side
    77.78x = 8,320.67
  5. Step 5: Solve for x
    x = 8,320.67/77.78
  6. Step 6: Final answer
    x = 106.97

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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.