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Finding the Fourth Proportional to 221.09, 305.09 and 138.24

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Solution

The fourth proportional to 221.09, 305.09 and 138.24 is: 190.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.09 : 305.09 = 138.24 : x
  2. Step 2: Convert to fraction form
    221.09/305.09 = 138.24/x
  3. Step 3: Cross multiply
    221.09x = 305.09 × 138.24
  4. Step 4: Simplify right side
    221.09x = 42,173.81
  5. Step 5: Solve for x
    x = 42,173.81/221.09
  6. Step 6: Final answer
    x = 190.76

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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.