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Finding the Fourth Proportional to 209.60, 289.20 and 122.30

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Solution

The fourth proportional to 209.60, 289.20 and 122.30 is: 168.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.60 : 289.20 = 122.30 : x
  2. Step 2: Convert to fraction form
    209.60/289.20 = 122.30/x
  3. Step 3: Cross multiply
    209.60x = 289.20 × 122.30
  4. Step 4: Simplify right side
    209.60x = 35,369.16
  5. Step 5: Solve for x
    x = 35,369.16/209.60
  6. Step 6: Final answer
    x = 168.75

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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.