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Finding the Fourth Proportional to 426.62, 639.69 and 221.15

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Solution

The fourth proportional to 426.62, 639.69 and 221.15 is: 331.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.62 : 639.69 = 221.15 : x
  2. Step 2: Convert to fraction form
    426.62/639.69 = 221.15/x
  3. Step 3: Cross multiply
    426.62x = 639.69 × 221.15
  4. Step 4: Simplify right side
    426.62x = 141,467.44
  5. Step 5: Solve for x
    x = 141,467.44/426.62
  6. Step 6: Final answer
    x = 331.60

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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.