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Finding the Fourth Proportional to 209.66, 289.31 and 126.72

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Solution

The fourth proportional to 209.66, 289.31 and 126.72 is: 174.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.66 : 289.31 = 126.72 : x
  2. Step 2: Convert to fraction form
    209.66/289.31 = 126.72/x
  3. Step 3: Cross multiply
    209.66x = 289.31 × 126.72
  4. Step 4: Simplify right side
    209.66x = 36,660.73
  5. Step 5: Solve for x
    x = 36,660.73/209.66
  6. Step 6: Final answer
    x = 174.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.