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Finding the Fourth Proportional to 221.45, 331.90 and 118.78

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Solution

The fourth proportional to 221.45, 331.90 and 118.78 is: 178.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.45 : 331.90 = 118.78 : x
  2. Step 2: Convert to fraction form
    221.45/331.90 = 118.78/x
  3. Step 3: Cross multiply
    221.45x = 331.90 × 118.78
  4. Step 4: Simplify right side
    221.45x = 39,421.96
  5. Step 5: Solve for x
    x = 39,421.96/221.45
  6. Step 6: Final answer
    x = 178.02

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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.