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Finding the Fourth Proportional to 128.62, 191.89 and 108.46

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Solution

The fourth proportional to 128.62, 191.89 and 108.46 is: 161.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.62 : 191.89 = 108.46 : x
  2. Step 2: Convert to fraction form
    128.62/191.89 = 108.46/x
  3. Step 3: Cross multiply
    128.62x = 191.89 × 108.46
  4. Step 4: Simplify right side
    128.62x = 20,812.39
  5. Step 5: Solve for x
    x = 20,812.39/128.62
  6. Step 6: Final answer
    x = 161.81

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.