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Finding the Fourth Proportional to 221.10, 305.12 and 138.21

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Solution

The fourth proportional to 221.10, 305.12 and 138.21 is: 190.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.10 : 305.12 = 138.21 : x
  2. Step 2: Convert to fraction form
    221.10/305.12 = 138.21/x
  3. Step 3: Cross multiply
    221.10x = 305.12 × 138.21
  4. Step 4: Simplify right side
    221.10x = 42,170.64
  5. Step 5: Solve for x
    x = 42,170.64/221.10
  6. Step 6: Final answer
    x = 190.73

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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.