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Finding the Fourth Proportional to 398.91, 550.50 and 221.88

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Solution

The fourth proportional to 398.91, 550.50 and 221.88 is: 306.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.91 : 550.50 = 221.88 : x
  2. Step 2: Convert to fraction form
    398.91/550.50 = 221.88/x
  3. Step 3: Cross multiply
    398.91x = 550.50 × 221.88
  4. Step 4: Simplify right side
    398.91x = 122,145.07
  5. Step 5: Solve for x
    x = 122,145.07/398.91
  6. Step 6: Final answer
    x = 306.20

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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.