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Finding the Fourth Proportional to 121.20, 180.84 and 113.85

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Solution

The fourth proportional to 121.20, 180.84 and 113.85 is: 169.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.20 : 180.84 = 113.85 : x
  2. Step 2: Convert to fraction form
    121.20/180.84 = 113.85/x
  3. Step 3: Cross multiply
    121.20x = 180.84 × 113.85
  4. Step 4: Simplify right side
    121.20x = 20,588.63
  5. Step 5: Solve for x
    x = 20,588.63/121.20
  6. Step 6: Final answer
    x = 169.88

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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.