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Finding the Fourth Proportional to 79.92, 120.39 and 75.12

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Solution

The fourth proportional to 79.92, 120.39 and 75.12 is: 113.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.92 : 120.39 = 75.12 : x
  2. Step 2: Convert to fraction form
    79.92/120.39 = 75.12/x
  3. Step 3: Cross multiply
    79.92x = 120.39 × 75.12
  4. Step 4: Simplify right side
    79.92x = 9,043.70
  5. Step 5: Solve for x
    x = 9,043.70/79.92
  6. Step 6: Final answer
    x = 113.16

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.