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Finding the Fourth Proportional to 219.87, 329.58 and 128.61

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Solution

The fourth proportional to 219.87, 329.58 and 128.61 is: 192.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.87 : 329.58 = 128.61 : x
  2. Step 2: Convert to fraction form
    219.87/329.58 = 128.61/x
  3. Step 3: Cross multiply
    219.87x = 329.58 × 128.61
  4. Step 4: Simplify right side
    219.87x = 42,387.28
  5. Step 5: Solve for x
    x = 42,387.28/219.87
  6. Step 6: Final answer
    x = 192.78

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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.