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Finding the Fourth Proportional to 198.78, 298.19 and 61.81

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Solution

The fourth proportional to 198.78, 298.19 and 61.81 is: 92.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.78 : 298.19 = 61.81 : x
  2. Step 2: Convert to fraction form
    198.78/298.19 = 61.81/x
  3. Step 3: Cross multiply
    198.78x = 298.19 × 61.81
  4. Step 4: Simplify right side
    198.78x = 18,430.53
  5. Step 5: Solve for x
    x = 18,430.53/198.78
  6. Step 6: Final answer
    x = 92.72

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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.