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Finding the Fourth Proportional to 321.86, 482.80 and 139.12

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Solution

The fourth proportional to 321.86, 482.80 and 139.12 is: 208.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.86 : 482.80 = 139.12 : x
  2. Step 2: Convert to fraction form
    321.86/482.80 = 139.12/x
  3. Step 3: Cross multiply
    321.86x = 482.80 × 139.12
  4. Step 4: Simplify right side
    321.86x = 67,167.14
  5. Step 5: Solve for x
    x = 67,167.14/321.86
  6. Step 6: Final answer
    x = 208.68

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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.