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Finding the Fourth Proportional to 321.11, 481.71 and 128.69

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Solution

The fourth proportional to 321.11, 481.71 and 128.69 is: 193.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.11 : 481.71 = 128.69 : x
  2. Step 2: Convert to fraction form
    321.11/481.71 = 128.69/x
  3. Step 3: Cross multiply
    321.11x = 481.71 × 128.69
  4. Step 4: Simplify right side
    321.11x = 61,991.26
  5. Step 5: Solve for x
    x = 61,991.26/321.11
  6. Step 6: Final answer
    x = 193.05

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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.