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Finding the Fourth Proportional to 138.19, 190.85 and 106.80

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Solution

The fourth proportional to 138.19, 190.85 and 106.80 is: 147.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.19 : 190.85 = 106.80 : x
  2. Step 2: Convert to fraction form
    138.19/190.85 = 106.80/x
  3. Step 3: Cross multiply
    138.19x = 190.85 × 106.80
  4. Step 4: Simplify right side
    138.19x = 20,382.78
  5. Step 5: Solve for x
    x = 20,382.78/138.19
  6. Step 6: Final answer
    x = 147.50

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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.