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Finding the Fourth Proportional to 128.89, 193.36 and 55.81

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Solution

The fourth proportional to 128.89, 193.36 and 55.81 is: 83.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.89 : 193.36 = 55.81 : x
  2. Step 2: Convert to fraction form
    128.89/193.36 = 55.81/x
  3. Step 3: Cross multiply
    128.89x = 193.36 × 55.81
  4. Step 4: Simplify right side
    128.89x = 10,791.42
  5. Step 5: Solve for x
    x = 10,791.42/128.89
  6. Step 6: Final answer
    x = 83.73

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.