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Finding the Fourth Proportional to 138.12, 208.23 and 123.09

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Solution

The fourth proportional to 138.12, 208.23 and 123.09 is: 185.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.12 : 208.23 = 123.09 : x
  2. Step 2: Convert to fraction form
    138.12/208.23 = 123.09/x
  3. Step 3: Cross multiply
    138.12x = 208.23 × 123.09
  4. Step 4: Simplify right side
    138.12x = 25,631.03
  5. Step 5: Solve for x
    x = 25,631.03/138.12
  6. Step 6: Final answer
    x = 185.57

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.