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Finding the Fourth Proportional to 218.50, 327.69 and 81.60

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Solution

The fourth proportional to 218.50, 327.69 and 81.60 is: 122.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.50 : 327.69 = 81.60 : x
  2. Step 2: Convert to fraction form
    218.50/327.69 = 81.60/x
  3. Step 3: Cross multiply
    218.50x = 327.69 × 81.60
  4. Step 4: Simplify right side
    218.50x = 26,739.50
  5. Step 5: Solve for x
    x = 26,739.50/218.50
  6. Step 6: Final answer
    x = 122.38

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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.