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Finding the Fourth Proportional to 198.78, 274.31 and 115.91

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Solution

The fourth proportional to 198.78, 274.31 and 115.91 is: 159.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.78 : 274.31 = 115.91 : x
  2. Step 2: Convert to fraction form
    198.78/274.31 = 115.91/x
  3. Step 3: Cross multiply
    198.78x = 274.31 × 115.91
  4. Step 4: Simplify right side
    198.78x = 31,795.27
  5. Step 5: Solve for x
    x = 31,795.27/198.78
  6. Step 6: Final answer
    x = 159.95

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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.