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Finding the Fourth Proportional to 206.78, 309.65 and 109.36

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Solution

The fourth proportional to 206.78, 309.65 and 109.36 is: 163.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.78 : 309.65 = 109.36 : x
  2. Step 2: Convert to fraction form
    206.78/309.65 = 109.36/x
  3. Step 3: Cross multiply
    206.78x = 309.65 × 109.36
  4. Step 4: Simplify right side
    206.78x = 33,862.82
  5. Step 5: Solve for x
    x = 33,862.82/206.78
  6. Step 6: Final answer
    x = 163.77

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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.