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Finding the Fourth Proportional to 321.90, 483.06 and 139.38

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Solution

The fourth proportional to 321.90, 483.06 and 139.38 is: 209.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.90 : 483.06 = 139.38 : x
  2. Step 2: Convert to fraction form
    321.90/483.06 = 139.38/x
  3. Step 3: Cross multiply
    321.90x = 483.06 × 139.38
  4. Step 4: Simplify right side
    321.90x = 67,328.90
  5. Step 5: Solve for x
    x = 67,328.90/321.90
  6. Step 6: Final answer
    x = 209.16

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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.