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Finding the Fourth Proportional to 209.90, 289.64 and 122.55

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Solution

The fourth proportional to 209.90, 289.64 and 122.55 is: 169.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.90 : 289.64 = 122.55 : x
  2. Step 2: Convert to fraction form
    209.90/289.64 = 122.55/x
  3. Step 3: Cross multiply
    209.90x = 289.64 × 122.55
  4. Step 4: Simplify right side
    209.90x = 35,494.77
  5. Step 5: Solve for x
    x = 35,494.77/209.90
  6. Step 6: Final answer
    x = 169.11

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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.