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Finding the Fourth Proportional to 128.11, 191.76 and 89.41

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Solution

The fourth proportional to 128.11, 191.76 and 89.41 is: 133.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.11 : 191.76 = 89.41 : x
  2. Step 2: Convert to fraction form
    128.11/191.76 = 89.41/x
  3. Step 3: Cross multiply
    128.11x = 191.76 × 89.41
  4. Step 4: Simplify right side
    128.11x = 17,145.26
  5. Step 5: Solve for x
    x = 17,145.26/128.11
  6. Step 6: Final answer
    x = 133.83

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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.