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Finding the Fourth Proportional to 218.08, 326.91 and 81.09

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Solution

The fourth proportional to 218.08, 326.91 and 81.09 is: 121.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.08 : 326.91 = 81.09 : x
  2. Step 2: Convert to fraction form
    218.08/326.91 = 81.09/x
  3. Step 3: Cross multiply
    218.08x = 326.91 × 81.09
  4. Step 4: Simplify right side
    218.08x = 26,509.13
  5. Step 5: Solve for x
    x = 26,509.13/218.08
  6. Step 6: Final answer
    x = 121.56

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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.