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Finding the Fourth Proportional to 219.85, 329.40 and 142.70

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Solution

The fourth proportional to 219.85, 329.40 and 142.70 is: 213.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.85 : 329.40 = 142.70 : x
  2. Step 2: Convert to fraction form
    219.85/329.40 = 142.70/x
  3. Step 3: Cross multiply
    219.85x = 329.40 × 142.70
  4. Step 4: Simplify right side
    219.85x = 47,003.73
  5. Step 5: Solve for x
    x = 47,003.73/219.85
  6. Step 6: Final answer
    x = 213.80

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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.