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Finding the Fourth Proportional to 120.31, 180.38 and 51.80

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Solution

The fourth proportional to 120.31, 180.38 and 51.80 is: 77.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.31 : 180.38 = 51.80 : x
  2. Step 2: Convert to fraction form
    120.31/180.38 = 51.80/x
  3. Step 3: Cross multiply
    120.31x = 180.38 × 51.80
  4. Step 4: Simplify right side
    120.31x = 9,342.91
  5. Step 5: Solve for x
    x = 9,342.91/120.31
  6. Step 6: Final answer
    x = 77.66

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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.