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Finding the Fourth Proportional to 121.66, 168.09 and 107.86

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Solution

The fourth proportional to 121.66, 168.09 and 107.86 is: 149.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.66 : 168.09 = 107.86 : x
  2. Step 2: Convert to fraction form
    121.66/168.09 = 107.86/x
  3. Step 3: Cross multiply
    121.66x = 168.09 × 107.86
  4. Step 4: Simplify right side
    121.66x = 18,130.19
  5. Step 5: Solve for x
    x = 18,130.19/121.66
  6. Step 6: Final answer
    x = 149.02

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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.