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Finding the Fourth Proportional to 80.98, 111.71 and 77.87

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Solution

The fourth proportional to 80.98, 111.71 and 77.87 is: 107.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.98 : 111.71 = 77.87 : x
  2. Step 2: Convert to fraction form
    80.98/111.71 = 77.87/x
  3. Step 3: Cross multiply
    80.98x = 111.71 × 77.87
  4. Step 4: Simplify right side
    80.98x = 8,698.86
  5. Step 5: Solve for x
    x = 8,698.86/80.98
  6. Step 6: Final answer
    x = 107.43

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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.