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Finding the Fourth Proportional to 321.90, 482.98 and 139.42

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Solution

The fourth proportional to 321.90, 482.98 and 139.42 is: 209.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.90 : 482.98 = 139.42 : x
  2. Step 2: Convert to fraction form
    321.90/482.98 = 139.42/x
  3. Step 3: Cross multiply
    321.90x = 482.98 × 139.42
  4. Step 4: Simplify right side
    321.90x = 67,338.95
  5. Step 5: Solve for x
    x = 67,338.95/321.90
  6. Step 6: Final answer
    x = 209.19

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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.