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Finding the Fourth Proportional to 221.21, 306.69 and 208.91

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Solution

The fourth proportional to 221.21, 306.69 and 208.91 is: 289.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.21 : 306.69 = 208.91 : x
  2. Step 2: Convert to fraction form
    221.21/306.69 = 208.91/x
  3. Step 3: Cross multiply
    221.21x = 306.69 × 208.91
  4. Step 4: Simplify right side
    221.21x = 64,072.35
  5. Step 5: Solve for x
    x = 64,072.35/221.21
  6. Step 6: Final answer
    x = 289.64

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.