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Finding the Fourth Proportional to 209.70, 289.35 and 122.31

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Solution

The fourth proportional to 209.70, 289.35 and 122.31 is: 168.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.70 : 289.35 = 122.31 : x
  2. Step 2: Convert to fraction form
    209.70/289.35 = 122.31/x
  3. Step 3: Cross multiply
    209.70x = 289.35 × 122.31
  4. Step 4: Simplify right side
    209.70x = 35,390.40
  5. Step 5: Solve for x
    x = 35,390.40/209.70
  6. Step 6: Final answer
    x = 168.77

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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.