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Finding the Fourth Proportional to 221.40, 305.57 and 138.54

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Solution

The fourth proportional to 221.40, 305.57 and 138.54 is: 191.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.40 : 305.57 = 138.54 : x
  2. Step 2: Convert to fraction form
    221.40/305.57 = 138.54/x
  3. Step 3: Cross multiply
    221.40x = 305.57 × 138.54
  4. Step 4: Simplify right side
    221.40x = 42,333.67
  5. Step 5: Solve for x
    x = 42,333.67/221.40
  6. Step 6: Final answer
    x = 191.21

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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.