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Finding the Fourth Proportional to 128.19, 176.92 and 83.92

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Solution

The fourth proportional to 128.19, 176.92 and 83.92 is: 115.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.19 : 176.92 = 83.92 : x
  2. Step 2: Convert to fraction form
    128.19/176.92 = 83.92/x
  3. Step 3: Cross multiply
    128.19x = 176.92 × 83.92
  4. Step 4: Simplify right side
    128.19x = 14,847.13
  5. Step 5: Solve for x
    x = 14,847.13/128.19
  6. Step 6: Final answer
    x = 115.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.