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Finding the Fourth Proportional to 398.69, 550.17 and 221.66

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Solution

The fourth proportional to 398.69, 550.17 and 221.66 is: 305.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.69 : 550.17 = 221.66 : x
  2. Step 2: Convert to fraction form
    398.69/550.17 = 221.66/x
  3. Step 3: Cross multiply
    398.69x = 550.17 × 221.66
  4. Step 4: Simplify right side
    398.69x = 121,947.93
  5. Step 5: Solve for x
    x = 121,947.93/398.69
  6. Step 6: Final answer
    x = 305.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.