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Finding the Fourth Proportional to 128.20, 192.36 and 55.05

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Solution

The fourth proportional to 128.20, 192.36 and 55.05 is: 82.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.20 : 192.36 = 55.05 : x
  2. Step 2: Convert to fraction form
    128.20/192.36 = 55.05/x
  3. Step 3: Cross multiply
    128.20x = 192.36 × 55.05
  4. Step 4: Simplify right side
    128.20x = 10,589.78
  5. Step 5: Solve for x
    x = 10,589.78/128.20
  6. Step 6: Final answer
    x = 82.60

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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.