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Finding the Fourth Proportional to 221.16, 331.80 and 91.17

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Solution

The fourth proportional to 221.16, 331.80 and 91.17 is: 136.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.16 : 331.80 = 91.17 : x
  2. Step 2: Convert to fraction form
    221.16/331.80 = 91.17/x
  3. Step 3: Cross multiply
    221.16x = 331.80 × 91.17
  4. Step 4: Simplify right side
    221.16x = 30,250.21
  5. Step 5: Solve for x
    x = 30,250.21/221.16
  6. Step 6: Final answer
    x = 136.78

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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.