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Finding the Fourth Proportional to 221.07, 331.62 and 76.80

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Solution

The fourth proportional to 221.07, 331.62 and 76.80 is: 115.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.07 : 331.62 = 76.80 : x
  2. Step 2: Convert to fraction form
    221.07/331.62 = 76.80/x
  3. Step 3: Cross multiply
    221.07x = 331.62 × 76.80
  4. Step 4: Simplify right side
    221.07x = 25,468.42
  5. Step 5: Solve for x
    x = 25,468.42/221.07
  6. Step 6: Final answer
    x = 115.21

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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.