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Finding the Fourth Proportional to 121.83, 168.09 and 80.38

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Solution

The fourth proportional to 121.83, 168.09 and 80.38 is: 110.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.83 : 168.09 = 80.38 : x
  2. Step 2: Convert to fraction form
    121.83/168.09 = 80.38/x
  3. Step 3: Cross multiply
    121.83x = 168.09 × 80.38
  4. Step 4: Simplify right side
    121.83x = 13,511.07
  5. Step 5: Solve for x
    x = 13,511.07/121.83
  6. Step 6: Final answer
    x = 110.90

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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.