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Finding the Fourth Proportional to 198.40, 273.76 and 128.55

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Solution

The fourth proportional to 198.40, 273.76 and 128.55 is: 177.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.40 : 273.76 = 128.55 : x
  2. Step 2: Convert to fraction form
    198.40/273.76 = 128.55/x
  3. Step 3: Cross multiply
    198.40x = 273.76 × 128.55
  4. Step 4: Simplify right side
    198.40x = 35,191.21
  5. Step 5: Solve for x
    x = 35,191.21/198.40
  6. Step 6: Final answer
    x = 177.38

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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.