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Finding the Fourth Proportional to 209.64, 289.21 and 122.29

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Solution

The fourth proportional to 209.64, 289.21 and 122.29 is: 168.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.64 : 289.21 = 122.29 : x
  2. Step 2: Convert to fraction form
    209.64/289.21 = 122.29/x
  3. Step 3: Cross multiply
    209.64x = 289.21 × 122.29
  4. Step 4: Simplify right side
    209.64x = 35,367.49
  5. Step 5: Solve for x
    x = 35,367.49/209.64
  6. Step 6: Final answer
    x = 168.71

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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.