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Finding the Fourth Proportional to 198.48, 273.98 and 128.72

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Solution

The fourth proportional to 198.48, 273.98 and 128.72 is: 177.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.48 : 273.98 = 128.72 : x
  2. Step 2: Convert to fraction form
    198.48/273.98 = 128.72/x
  3. Step 3: Cross multiply
    198.48x = 273.98 × 128.72
  4. Step 4: Simplify right side
    198.48x = 35,266.71
  5. Step 5: Solve for x
    x = 35,266.71/198.48
  6. Step 6: Final answer
    x = 177.68

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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.