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Finding the Fourth Proportional to 121.88, 168.08 and 80.39

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Solution

The fourth proportional to 121.88, 168.08 and 80.39 is: 110.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.88 : 168.08 = 80.39 : x
  2. Step 2: Convert to fraction form
    121.88/168.08 = 80.39/x
  3. Step 3: Cross multiply
    121.88x = 168.08 × 80.39
  4. Step 4: Simplify right side
    121.88x = 13,511.97
  5. Step 5: Solve for x
    x = 13,511.97/121.88
  6. Step 6: Final answer
    x = 110.86

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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.