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Finding the Fourth Proportional to 322.45, 483.78 and 139.90

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Solution

The fourth proportional to 322.45, 483.78 and 139.90 is: 209.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    322.45 : 483.78 = 139.90 : x
  2. Step 2: Convert to fraction form
    322.45/483.78 = 139.90/x
  3. Step 3: Cross multiply
    322.45x = 483.78 × 139.90
  4. Step 4: Simplify right side
    322.45x = 67,680.82
  5. Step 5: Solve for x
    x = 67,680.82/322.45
  6. Step 6: Final answer
    x = 209.90

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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.