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Finding the Fourth Proportional to 128.79, 192.92 and 79.92

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Solution

The fourth proportional to 128.79, 192.92 and 79.92 is: 119.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.79 : 192.92 = 79.92 : x
  2. Step 2: Convert to fraction form
    128.79/192.92 = 79.92/x
  3. Step 3: Cross multiply
    128.79x = 192.92 × 79.92
  4. Step 4: Simplify right side
    128.79x = 15,418.37
  5. Step 5: Solve for x
    x = 15,418.37/128.79
  6. Step 6: Final answer
    x = 119.72

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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.