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Finding the Fourth Proportional to 136.69, 188.85 and 121.80

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Solution

The fourth proportional to 136.69, 188.85 and 121.80 is: 168.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.69 : 188.85 = 121.80 : x
  2. Step 2: Convert to fraction form
    136.69/188.85 = 121.80/x
  3. Step 3: Cross multiply
    136.69x = 188.85 × 121.80
  4. Step 4: Simplify right side
    136.69x = 23,003.09
  5. Step 5: Solve for x
    x = 23,003.09/136.69
  6. Step 6: Final answer
    x = 168.29

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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.