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Finding the Fourth Proportional to 221.63, 331.96 and 128.87

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Solution

The fourth proportional to 221.63, 331.96 and 128.87 is: 193.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.63 : 331.96 = 128.87 : x
  2. Step 2: Convert to fraction form
    221.63/331.96 = 128.87/x
  3. Step 3: Cross multiply
    221.63x = 331.96 × 128.87
  4. Step 4: Simplify right side
    221.63x = 42,779.69
  5. Step 5: Solve for x
    x = 42,779.69/221.63
  6. Step 6: Final answer
    x = 193.02

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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.