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Finding the Fourth Proportional to 138.25, 206.97 and 76.42

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Solution

The fourth proportional to 138.25, 206.97 and 76.42 is: 114.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.25 : 206.97 = 76.42 : x
  2. Step 2: Convert to fraction form
    138.25/206.97 = 76.42/x
  3. Step 3: Cross multiply
    138.25x = 206.97 × 76.42
  4. Step 4: Simplify right side
    138.25x = 15,816.65
  5. Step 5: Solve for x
    x = 15,816.65/138.25
  6. Step 6: Final answer
    x = 114.41

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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.