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Finding the Fourth Proportional to 398.82, 550.40 and 221.81

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Solution

The fourth proportional to 398.82, 550.40 and 221.81 is: 306.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.82 : 550.40 = 221.81 : x
  2. Step 2: Convert to fraction form
    398.82/550.40 = 221.81/x
  3. Step 3: Cross multiply
    398.82x = 550.40 × 221.81
  4. Step 4: Simplify right side
    398.82x = 122,084.22
  5. Step 5: Solve for x
    x = 122,084.22/398.82
  6. Step 6: Final answer
    x = 306.12

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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.