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Finding the Fourth Proportional to 128.07, 192.09 and 31.88

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Solution

The fourth proportional to 128.07, 192.09 and 31.88 is: 47.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.07 : 192.09 = 31.88 : x
  2. Step 2: Convert to fraction form
    128.07/192.09 = 31.88/x
  3. Step 3: Cross multiply
    128.07x = 192.09 × 31.88
  4. Step 4: Simplify right side
    128.07x = 6,122.87
  5. Step 5: Solve for x
    x = 6,122.87/128.07
  6. Step 6: Final answer
    x = 47.81

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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.