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Finding the Fourth Proportional to 120.81, 180.24 and 108.42

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Solution

The fourth proportional to 120.81, 180.24 and 108.42 is: 161.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.81 : 180.24 = 108.42 : x
  2. Step 2: Convert to fraction form
    120.81/180.24 = 108.42/x
  3. Step 3: Cross multiply
    120.81x = 180.24 × 108.42
  4. Step 4: Simplify right side
    120.81x = 19,541.62
  5. Step 5: Solve for x
    x = 19,541.62/120.81
  6. Step 6: Final answer
    x = 161.75

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.