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Finding the Fourth Proportional to 120.70, 180.81 and 69.31

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Solution

The fourth proportional to 120.70, 180.81 and 69.31 is: 103.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.70 : 180.81 = 69.31 : x
  2. Step 2: Convert to fraction form
    120.70/180.81 = 69.31/x
  3. Step 3: Cross multiply
    120.70x = 180.81 × 69.31
  4. Step 4: Simplify right side
    120.70x = 12,531.94
  5. Step 5: Solve for x
    x = 12,531.94/120.70
  6. Step 6: Final answer
    x = 103.83

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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.