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Finding the Fourth Proportional to 138.23, 206.96 and 80.36

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Solution

The fourth proportional to 138.23, 206.96 and 80.36 is: 120.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.23 : 206.96 = 80.36 : x
  2. Step 2: Convert to fraction form
    138.23/206.96 = 80.36/x
  3. Step 3: Cross multiply
    138.23x = 206.96 × 80.36
  4. Step 4: Simplify right side
    138.23x = 16,629.87
  5. Step 5: Solve for x
    x = 16,629.87/138.23
  6. Step 6: Final answer
    x = 120.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.