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Finding the Fourth Proportional to 209.63, 289.28 and 122.30

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Solution

The fourth proportional to 209.63, 289.28 and 122.30 is: 168.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.63 : 289.28 = 122.30 : x
  2. Step 2: Convert to fraction form
    209.63/289.28 = 122.30/x
  3. Step 3: Cross multiply
    209.63x = 289.28 × 122.30
  4. Step 4: Simplify right side
    209.63x = 35,379.97
  5. Step 5: Solve for x
    x = 35,379.97/209.63
  6. Step 6: Final answer
    x = 168.78

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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.