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Finding the Fourth Proportional to 221.08, 328.92 and 209.56

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Solution

The fourth proportional to 221.08, 328.92 and 209.56 is: 311.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.08 : 328.92 = 209.56 : x
  2. Step 2: Convert to fraction form
    221.08/328.92 = 209.56/x
  3. Step 3: Cross multiply
    221.08x = 328.92 × 209.56
  4. Step 4: Simplify right side
    221.08x = 68,928.48
  5. Step 5: Solve for x
    x = 68,928.48/221.08
  6. Step 6: Final answer
    x = 311.78

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.