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Finding the Fourth Proportional to 128.18, 191.96 and 91.94

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Solution

The fourth proportional to 128.18, 191.96 and 91.94 is: 137.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.18 : 191.96 = 91.94 : x
  2. Step 2: Convert to fraction form
    128.18/191.96 = 91.94/x
  3. Step 3: Cross multiply
    128.18x = 191.96 × 91.94
  4. Step 4: Simplify right side
    128.18x = 17,648.80
  5. Step 5: Solve for x
    x = 17,648.80/128.18
  6. Step 6: Final answer
    x = 137.69

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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.