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Finding the Fourth Proportional to 272.20, 408.18 and 79.78

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Solution

The fourth proportional to 272.20, 408.18 and 79.78 is: 119.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    272.20 : 408.18 = 79.78 : x
  2. Step 2: Convert to fraction form
    272.20/408.18 = 79.78/x
  3. Step 3: Cross multiply
    272.20x = 408.18 × 79.78
  4. Step 4: Simplify right side
    272.20x = 32,564.60
  5. Step 5: Solve for x
    x = 32,564.60/272.20
  6. Step 6: Final answer
    x = 119.63

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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.