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Finding the Fourth Proportional to 209.63, 289.28 and 121.05

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Solution

The fourth proportional to 209.63, 289.28 and 121.05 is: 167.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.63 : 289.28 = 121.05 : x
  2. Step 2: Convert to fraction form
    209.63/289.28 = 121.05/x
  3. Step 3: Cross multiply
    209.63x = 289.28 × 121.05
  4. Step 4: Simplify right side
    209.63x = 35,017.65
  5. Step 5: Solve for x
    x = 35,017.65/209.63
  6. Step 6: Final answer
    x = 167.05

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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.