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Finding the Fourth Proportional to 206.05, 309.09 and 128.89

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Solution

The fourth proportional to 206.05, 309.09 and 128.89 is: 193.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.05 : 309.09 = 128.89 : x
  2. Step 2: Convert to fraction form
    206.05/309.09 = 128.89/x
  3. Step 3: Cross multiply
    206.05x = 309.09 × 128.89
  4. Step 4: Simplify right side
    206.05x = 39,838.61
  5. Step 5: Solve for x
    x = 39,838.61/206.05
  6. Step 6: Final answer
    x = 193.34

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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.