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Finding the Fourth Proportional to 121.20, 166.20 and 112.80

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Solution

The fourth proportional to 121.20, 166.20 and 112.80 is: 154.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.20 : 166.20 = 112.80 : x
  2. Step 2: Convert to fraction form
    121.20/166.20 = 112.80/x
  3. Step 3: Cross multiply
    121.20x = 166.20 × 112.80
  4. Step 4: Simplify right side
    121.20x = 18,747.36
  5. Step 5: Solve for x
    x = 18,747.36/121.20
  6. Step 6: Final answer
    x = 154.68

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.