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Finding the Fourth Proportional to 209.97, 315.02 and 81.81

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Solution

The fourth proportional to 209.97, 315.02 and 81.81 is: 122.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.97 : 315.02 = 81.81 : x
  2. Step 2: Convert to fraction form
    209.97/315.02 = 81.81/x
  3. Step 3: Cross multiply
    209.97x = 315.02 × 81.81
  4. Step 4: Simplify right side
    209.97x = 25,771.38
  5. Step 5: Solve for x
    x = 25,771.38/209.97
  6. Step 6: Final answer
    x = 122.74

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.