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Finding the Fourth Proportional to 398.72, 550.26 and 221.69

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Solution

The fourth proportional to 398.72, 550.26 and 221.69 is: 305.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.72 : 550.26 = 221.69 : x
  2. Step 2: Convert to fraction form
    398.72/550.26 = 221.69/x
  3. Step 3: Cross multiply
    398.72x = 550.26 × 221.69
  4. Step 4: Simplify right side
    398.72x = 121,987.14
  5. Step 5: Solve for x
    x = 121,987.14/398.72
  6. Step 6: Final answer
    x = 305.95

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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.