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Finding the Fourth Proportional to 209.29, 288.81 and 121.96

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Solution

The fourth proportional to 209.29, 288.81 and 121.96 is: 168.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.29 : 288.81 = 121.96 : x
  2. Step 2: Convert to fraction form
    209.29/288.81 = 121.96/x
  3. Step 3: Cross multiply
    209.29x = 288.81 × 121.96
  4. Step 4: Simplify right side
    209.29x = 35,223.27
  5. Step 5: Solve for x
    x = 35,223.27/209.29
  6. Step 6: Final answer
    x = 168.30

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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.