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Finding the Fourth Proportional to 220.98, 330.78 and 139.42

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Solution

The fourth proportional to 220.98, 330.78 and 139.42 is: 208.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.98 : 330.78 = 139.42 : x
  2. Step 2: Convert to fraction form
    220.98/330.78 = 139.42/x
  3. Step 3: Cross multiply
    220.98x = 330.78 × 139.42
  4. Step 4: Simplify right side
    220.98x = 46,118.28
  5. Step 5: Solve for x
    x = 46,118.28/220.98
  6. Step 6: Final answer
    x = 208.70

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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.