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Finding the Fourth Proportional to 138.12, 206.94 and 103.80

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Solution

The fourth proportional to 138.12, 206.94 and 103.80 is: 155.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.12 : 206.94 = 103.80 : x
  2. Step 2: Convert to fraction form
    138.12/206.94 = 103.80/x
  3. Step 3: Cross multiply
    138.12x = 206.94 × 103.80
  4. Step 4: Simplify right side
    138.12x = 21,480.37
  5. Step 5: Solve for x
    x = 21,480.37/138.12
  6. Step 6: Final answer
    x = 155.52

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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.