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Finding the Fourth Proportional to 209.90, 289.63 and 122.57

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Solution

The fourth proportional to 209.90, 289.63 and 122.57 is: 169.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.90 : 289.63 = 122.57 : x
  2. Step 2: Convert to fraction form
    209.90/289.63 = 122.57/x
  3. Step 3: Cross multiply
    209.90x = 289.63 × 122.57
  4. Step 4: Simplify right side
    209.90x = 35,499.95
  5. Step 5: Solve for x
    x = 35,499.95/209.90
  6. Step 6: Final answer
    x = 169.13

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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.