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Finding the Fourth Proportional to 321.91, 482.97 and 139.21

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Solution

The fourth proportional to 321.91, 482.97 and 139.21 is: 208.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.91 : 482.97 = 139.21 : x
  2. Step 2: Convert to fraction form
    321.91/482.97 = 139.21/x
  3. Step 3: Cross multiply
    321.91x = 482.97 × 139.21
  4. Step 4: Simplify right side
    321.91x = 67,234.25
  5. Step 5: Solve for x
    x = 67,234.25/321.91
  6. Step 6: Final answer
    x = 208.86

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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.