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Finding the Fourth Proportional to 221.48, 305.53 and 142.78

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Solution

The fourth proportional to 221.48, 305.53 and 142.78 is: 196.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.48 : 305.53 = 142.78 : x
  2. Step 2: Convert to fraction form
    221.48/305.53 = 142.78/x
  3. Step 3: Cross multiply
    221.48x = 305.53 × 142.78
  4. Step 4: Simplify right side
    221.48x = 43,623.57
  5. Step 5: Solve for x
    x = 43,623.57/221.48
  6. Step 6: Final answer
    x = 196.96

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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.