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Finding the Fourth Proportional to 321.16, 481.81 and 138.55

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Solution

The fourth proportional to 321.16, 481.81 and 138.55 is: 207.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.16 : 481.81 = 138.55 : x
  2. Step 2: Convert to fraction form
    321.16/481.81 = 138.55/x
  3. Step 3: Cross multiply
    321.16x = 481.81 × 138.55
  4. Step 4: Simplify right side
    321.16x = 66,754.78
  5. Step 5: Solve for x
    x = 66,754.78/321.16
  6. Step 6: Final answer
    x = 207.86

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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.