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Finding the Fourth Proportional to 120.46, 180.75 and 81.91

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Solution

The fourth proportional to 120.46, 180.75 and 81.91 is: 122.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.46 : 180.75 = 81.91 : x
  2. Step 2: Convert to fraction form
    120.46/180.75 = 81.91/x
  3. Step 3: Cross multiply
    120.46x = 180.75 × 81.91
  4. Step 4: Simplify right side
    120.46x = 14,805.23
  5. Step 5: Solve for x
    x = 14,805.23/120.46
  6. Step 6: Final answer
    x = 122.91

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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.