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Finding the Fourth Proportional to 120.78, 179.92 and 113.31

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Solution

The fourth proportional to 120.78, 179.92 and 113.31 is: 168.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.78 : 179.92 = 113.31 : x
  2. Step 2: Convert to fraction form
    120.78/179.92 = 113.31/x
  3. Step 3: Cross multiply
    120.78x = 179.92 × 113.31
  4. Step 4: Simplify right side
    120.78x = 20,386.29
  5. Step 5: Solve for x
    x = 20,386.29/120.78
  6. Step 6: Final answer
    x = 168.79

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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.