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Finding the Fourth Proportional to 198.90, 274.45 and 120.20

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Solution

The fourth proportional to 198.90, 274.45 and 120.20 is: 165.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.90 : 274.45 = 120.20 : x
  2. Step 2: Convert to fraction form
    198.90/274.45 = 120.20/x
  3. Step 3: Cross multiply
    198.90x = 274.45 × 120.20
  4. Step 4: Simplify right side
    198.90x = 32,987.60
  5. Step 5: Solve for x
    x = 32,987.60/198.90
  6. Step 6: Final answer
    x = 165.85

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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.