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Finding the Fourth Proportional to 221.47, 331.68 and 213.78

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Solution

The fourth proportional to 221.47, 331.68 and 213.78 is: 320.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.47 : 331.68 = 213.78 : x
  2. Step 2: Convert to fraction form
    221.47/331.68 = 213.78/x
  3. Step 3: Cross multiply
    221.47x = 331.68 × 213.78
  4. Step 4: Simplify right side
    221.47x = 70,905.43
  5. Step 5: Solve for x
    x = 70,905.43/221.47
  6. Step 6: Final answer
    x = 320.17

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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.