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Finding the Fourth Proportional to 197.81, 272.87 and 128.81

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Solution

The fourth proportional to 197.81, 272.87 and 128.81 is: 177.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    197.81 : 272.87 = 128.81 : x
  2. Step 2: Convert to fraction form
    197.81/272.87 = 128.81/x
  3. Step 3: Cross multiply
    197.81x = 272.87 × 128.81
  4. Step 4: Simplify right side
    197.81x = 35,147.74
  5. Step 5: Solve for x
    x = 35,147.74/197.81
  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.