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Finding the Fourth Proportional to 198.78, 298.05 and 126.66

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Solution

The fourth proportional to 198.78, 298.05 and 126.66 is: 189.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.78 : 298.05 = 126.66 : x
  2. Step 2: Convert to fraction form
    198.78/298.05 = 126.66/x
  3. Step 3: Cross multiply
    198.78x = 298.05 × 126.66
  4. Step 4: Simplify right side
    198.78x = 37,751.01
  5. Step 5: Solve for x
    x = 37,751.01/198.78
  6. Step 6: Final answer
    x = 189.91

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.