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Finding the Fourth Proportional to 221.78, 305.70 and 197.18

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Solution

The fourth proportional to 221.78, 305.70 and 197.18 is: 271.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.78 : 305.70 = 197.18 : x
  2. Step 2: Convert to fraction form
    221.78/305.70 = 197.18/x
  3. Step 3: Cross multiply
    221.78x = 305.70 × 197.18
  4. Step 4: Simplify right side
    221.78x = 60,277.93
  5. Step 5: Solve for x
    x = 60,277.93/221.78
  6. Step 6: Final answer
    x = 271.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.