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Finding the Fourth Proportional to 221.09, 331.12 and 213.40

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Solution

The fourth proportional to 221.09, 331.12 and 213.40 is: 319.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.09 : 331.12 = 213.40 : x
  2. Step 2: Convert to fraction form
    221.09/331.12 = 213.40/x
  3. Step 3: Cross multiply
    221.09x = 331.12 × 213.40
  4. Step 4: Simplify right side
    221.09x = 70,661.29
  5. Step 5: Solve for x
    x = 70,661.29/221.09
  6. Step 6: Final answer
    x = 319.61

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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.