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Finding the Fourth Proportional to 209.55, 289.08 and 122.21

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Solution

The fourth proportional to 209.55, 289.08 and 122.21 is: 168.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.55 : 289.08 = 122.21 : x
  2. Step 2: Convert to fraction form
    209.55/289.08 = 122.21/x
  3. Step 3: Cross multiply
    209.55x = 289.08 × 122.21
  4. Step 4: Simplify right side
    209.55x = 35,327.02
  5. Step 5: Solve for x
    x = 35,327.02/209.55
  6. Step 6: Final answer
    x = 168.59

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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.