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Finding the Fourth Proportional to 128.08, 192.08 and 67.28

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Solution

The fourth proportional to 128.08, 192.08 and 67.28 is: 100.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.08 : 192.08 = 67.28 : x
  2. Step 2: Convert to fraction form
    128.08/192.08 = 67.28/x
  3. Step 3: Cross multiply
    128.08x = 192.08 × 67.28
  4. Step 4: Simplify right side
    128.08x = 12,923.14
  5. Step 5: Solve for x
    x = 12,923.14/128.08
  6. Step 6: Final answer
    x = 100.90

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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.