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Finding the Fourth Proportional to 220.18, 329.80 and 138.78

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Solution

The fourth proportional to 220.18, 329.80 and 138.78 is: 207.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.18 : 329.80 = 138.78 : x
  2. Step 2: Convert to fraction form
    220.18/329.80 = 138.78/x
  3. Step 3: Cross multiply
    220.18x = 329.80 × 138.78
  4. Step 4: Simplify right side
    220.18x = 45,769.64
  5. Step 5: Solve for x
    x = 45,769.64/220.18
  6. Step 6: Final answer
    x = 207.87

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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.