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Finding the Fourth Proportional to 77.15, 105.78 and 76.92

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Solution

The fourth proportional to 77.15, 105.78 and 76.92 is: 105.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.15 : 105.78 = 76.92 : x
  2. Step 2: Convert to fraction form
    77.15/105.78 = 76.92/x
  3. Step 3: Cross multiply
    77.15x = 105.78 × 76.92
  4. Step 4: Simplify right side
    77.15x = 8,137.17
  5. Step 5: Solve for x
    x = 8,137.17/77.15
  6. Step 6: Final answer
    x = 105.47

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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.