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Finding the Fourth Proportional to 217.78, 326.70 and 80.80

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Solution

The fourth proportional to 217.78, 326.70 and 80.80 is: 121.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.78 : 326.70 = 80.80 : x
  2. Step 2: Convert to fraction form
    217.78/326.70 = 80.80/x
  3. Step 3: Cross multiply
    217.78x = 326.70 × 80.80
  4. Step 4: Simplify right side
    217.78x = 26,397.36
  5. Step 5: Solve for x
    x = 26,397.36/217.78
  6. Step 6: Final answer
    x = 121.21

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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.