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Finding the Fourth Proportional to 79.92, 120.42 and 72.72

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Solution

The fourth proportional to 79.92, 120.42 and 72.72 is: 109.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.92 : 120.42 = 72.72 : x
  2. Step 2: Convert to fraction form
    79.92/120.42 = 72.72/x
  3. Step 3: Cross multiply
    79.92x = 120.42 × 72.72
  4. Step 4: Simplify right side
    79.92x = 8,756.94
  5. Step 5: Solve for x
    x = 8,756.94/79.92
  6. Step 6: Final answer
    x = 109.57

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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.