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Finding the Fourth Proportional to 138.61, 190.90 and 120.18

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Solution

The fourth proportional to 138.61, 190.90 and 120.18 is: 165.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.61 : 190.90 = 120.18 : x
  2. Step 2: Convert to fraction form
    138.61/190.90 = 120.18/x
  3. Step 3: Cross multiply
    138.61x = 190.90 × 120.18
  4. Step 4: Simplify right side
    138.61x = 22,942.06
  5. Step 5: Solve for x
    x = 22,942.06/138.61
  6. Step 6: Final answer
    x = 165.52

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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.