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Finding the Fourth Proportional to 221.08, 331.63 and 76.80

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Solution

The fourth proportional to 221.08, 331.63 and 76.80 is: 115.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.08 : 331.63 = 76.80 : x
  2. Step 2: Convert to fraction form
    221.08/331.63 = 76.80/x
  3. Step 3: Cross multiply
    221.08x = 331.63 × 76.80
  4. Step 4: Simplify right side
    221.08x = 25,469.18
  5. Step 5: Solve for x
    x = 25,469.18/221.08
  6. Step 6: Final answer
    x = 115.20

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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.