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Finding the Fourth Proportional to 426.71, 639.11 and 221.47

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Solution

The fourth proportional to 426.71, 639.11 and 221.47 is: 331.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.71 : 639.11 = 221.47 : x
  2. Step 2: Convert to fraction form
    426.71/639.11 = 221.47/x
  3. Step 3: Cross multiply
    426.71x = 639.11 × 221.47
  4. Step 4: Simplify right side
    426.71x = 141,542.65
  5. Step 5: Solve for x
    x = 141,542.65/426.71
  6. Step 6: Final answer
    x = 331.70

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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.