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Finding the Fourth Proportional to 77.45, 106.79 and 61.85

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Solution

The fourth proportional to 77.45, 106.79 and 61.85 is: 85.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.45 : 106.79 = 61.85 : x
  2. Step 2: Convert to fraction form
    77.45/106.79 = 61.85/x
  3. Step 3: Cross multiply
    77.45x = 106.79 × 61.85
  4. Step 4: Simplify right side
    77.45x = 6,604.92
  5. Step 5: Solve for x
    x = 6,604.92/77.45
  6. Step 6: Final answer
    x = 85.29

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.