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Finding the Fourth Proportional to 118.96, 178.44 and 81.20

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Solution

The fourth proportional to 118.96, 178.44 and 81.20 is: 121.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    118.96 : 178.44 = 81.20 : x
  2. Step 2: Convert to fraction form
    118.96/178.44 = 81.20/x
  3. Step 3: Cross multiply
    118.96x = 178.44 × 81.20
  4. Step 4: Simplify right side
    118.96x = 14,489.33
  5. Step 5: Solve for x
    x = 14,489.33/118.96
  6. Step 6: Final answer
    x = 121.80

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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.