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Finding the Fourth Proportional to 217.70, 326.49 and 78.86

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Solution

The fourth proportional to 217.70, 326.49 and 78.86 is: 118.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.70 : 326.49 = 78.86 : x
  2. Step 2: Convert to fraction form
    217.70/326.49 = 78.86/x
  3. Step 3: Cross multiply
    217.70x = 326.49 × 78.86
  4. Step 4: Simplify right side
    217.70x = 25,747.62
  5. Step 5: Solve for x
    x = 25,747.62/217.70
  6. Step 6: Final answer
    x = 118.27

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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.