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Finding the Fourth Proportional to 209.62, 289.30 and 121.11

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Solution

The fourth proportional to 209.62, 289.30 and 121.11 is: 167.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.62 : 289.30 = 121.11 : x
  2. Step 2: Convert to fraction form
    209.62/289.30 = 121.11/x
  3. Step 3: Cross multiply
    209.62x = 289.30 × 121.11
  4. Step 4: Simplify right side
    209.62x = 35,037.12
  5. Step 5: Solve for x
    x = 35,037.12/209.62
  6. Step 6: Final answer
    x = 167.15

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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.