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Finding the Fourth Proportional to 205.72, 308.49 and 128.68

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Solution

The fourth proportional to 205.72, 308.49 and 128.68 is: 192.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.72 : 308.49 = 128.68 : x
  2. Step 2: Convert to fraction form
    205.72/308.49 = 128.68/x
  3. Step 3: Cross multiply
    205.72x = 308.49 × 128.68
  4. Step 4: Simplify right side
    205.72x = 39,696.49
  5. Step 5: Solve for x
    x = 39,696.49/205.72
  6. Step 6: Final answer
    x = 192.96

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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.