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Finding the Fourth Proportional to 321.28, 481.81 and 138.64

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Solution

The fourth proportional to 321.28, 481.81 and 138.64 is: 207.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.28 : 481.81 = 138.64 : x
  2. Step 2: Convert to fraction form
    321.28/481.81 = 138.64/x
  3. Step 3: Cross multiply
    321.28x = 481.81 × 138.64
  4. Step 4: Simplify right side
    321.28x = 66,798.14
  5. Step 5: Solve for x
    x = 66,798.14/321.28
  6. Step 6: Final answer
    x = 207.91

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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.