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Finding the Fourth Proportional to 209.23, 288.70 and 121.89

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Solution

The fourth proportional to 209.23, 288.70 and 121.89 is: 168.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.23 : 288.70 = 121.89 : x
  2. Step 2: Convert to fraction form
    209.23/288.70 = 121.89/x
  3. Step 3: Cross multiply
    209.23x = 288.70 × 121.89
  4. Step 4: Simplify right side
    209.23x = 35,189.64
  5. Step 5: Solve for x
    x = 35,189.64/209.23
  6. Step 6: Final answer
    x = 168.19

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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.