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Finding the Fourth Proportional to 128.22, 191.74 and 105.09

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Solution

The fourth proportional to 128.22, 191.74 and 105.09 is: 157.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.22 : 191.74 = 105.09 : x
  2. Step 2: Convert to fraction form
    128.22/191.74 = 105.09/x
  3. Step 3: Cross multiply
    128.22x = 191.74 × 105.09
  4. Step 4: Simplify right side
    128.22x = 20,149.96
  5. Step 5: Solve for x
    x = 20,149.96/128.22
  6. Step 6: Final answer
    x = 157.15

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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.