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Finding the Fourth Proportional to 138.08, 190.54 and 82.78

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Solution

The fourth proportional to 138.08, 190.54 and 82.78 is: 114.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.08 : 190.54 = 82.78 : x
  2. Step 2: Convert to fraction form
    138.08/190.54 = 82.78/x
  3. Step 3: Cross multiply
    138.08x = 190.54 × 82.78
  4. Step 4: Simplify right side
    138.08x = 15,772.90
  5. Step 5: Solve for x
    x = 15,772.90/138.08
  6. Step 6: Final answer
    x = 114.23

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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.