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Finding the Fourth Proportional to 218.40, 327.61 and 81.45

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Solution

The fourth proportional to 218.40, 327.61 and 81.45 is: 122.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.40 : 327.61 = 81.45 : x
  2. Step 2: Convert to fraction form
    218.40/327.61 = 81.45/x
  3. Step 3: Cross multiply
    218.40x = 327.61 × 81.45
  4. Step 4: Simplify right side
    218.40x = 26,682.20
  5. Step 5: Solve for x
    x = 26,682.20/218.40
  6. Step 6: Final answer
    x = 122.17

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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.