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Finding the Fourth Proportional to 128.12, 191.97 and 115.56

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Solution

The fourth proportional to 128.12, 191.97 and 115.56 is: 173.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.12 : 191.97 = 115.56 : x
  2. Step 2: Convert to fraction form
    128.12/191.97 = 115.56/x
  3. Step 3: Cross multiply
    128.12x = 191.97 × 115.56
  4. Step 4: Simplify right side
    128.12x = 22,184.05
  5. Step 5: Solve for x
    x = 22,184.05/128.12
  6. Step 6: Final answer
    x = 173.16

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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.