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Finding the Fourth Proportional to 128.80, 194.11 and 122.68

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Solution

The fourth proportional to 128.80, 194.11 and 122.68 is: 184.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.80 : 194.11 = 122.68 : x
  2. Step 2: Convert to fraction form
    128.80/194.11 = 122.68/x
  3. Step 3: Cross multiply
    128.80x = 194.11 × 122.68
  4. Step 4: Simplify right side
    128.80x = 23,813.41
  5. Step 5: Solve for x
    x = 23,813.41/128.80
  6. Step 6: Final answer
    x = 184.89

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.