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Finding the Fourth Proportional to 120.85, 180.40 and 112.41

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Solution

The fourth proportional to 120.85, 180.40 and 112.41 is: 167.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.85 : 180.40 = 112.41 : x
  2. Step 2: Convert to fraction form
    120.85/180.40 = 112.41/x
  3. Step 3: Cross multiply
    120.85x = 180.40 × 112.41
  4. Step 4: Simplify right side
    120.85x = 20,278.20
  5. Step 5: Solve for x
    x = 20,278.20/120.85
  6. Step 6: Final answer
    x = 167.80

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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.