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Finding the Fourth Proportional to 128.12, 192.45 and 108.86

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Solution

The fourth proportional to 128.12, 192.45 and 108.86 is: 163.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.12 : 192.45 = 108.86 : x
  2. Step 2: Convert to fraction form
    128.12/192.45 = 108.86/x
  3. Step 3: Cross multiply
    128.12x = 192.45 × 108.86
  4. Step 4: Simplify right side
    128.12x = 20,950.11
  5. Step 5: Solve for x
    x = 20,950.11/128.12
  6. Step 6: Final answer
    x = 163.52

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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.