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Finding the Fourth Proportional to 220.98, 330.78 and 139.70

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Solution

The fourth proportional to 220.98, 330.78 and 139.70 is: 209.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.98 : 330.78 = 139.70 : x
  2. Step 2: Convert to fraction form
    220.98/330.78 = 139.70/x
  3. Step 3: Cross multiply
    220.98x = 330.78 × 139.70
  4. Step 4: Simplify right side
    220.98x = 46,209.97
  5. Step 5: Solve for x
    x = 46,209.97/220.98
  6. Step 6: Final answer
    x = 209.11

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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.