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Finding the Fourth Proportional to 209.54, 289.15 and 122.20

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Solution

The fourth proportional to 209.54, 289.15 and 122.20 is: 168.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.54 : 289.15 = 122.20 : x
  2. Step 2: Convert to fraction form
    209.54/289.15 = 122.20/x
  3. Step 3: Cross multiply
    209.54x = 289.15 × 122.20
  4. Step 4: Simplify right side
    209.54x = 35,334.13
  5. Step 5: Solve for x
    x = 35,334.13/209.54
  6. Step 6: Final answer
    x = 168.63

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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.