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Finding the Fourth Proportional to 120.98, 180.69 and 104.78

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Solution

The fourth proportional to 120.98, 180.69 and 104.78 is: 156.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.98 : 180.69 = 104.78 : x
  2. Step 2: Convert to fraction form
    120.98/180.69 = 104.78/x
  3. Step 3: Cross multiply
    120.98x = 180.69 × 104.78
  4. Step 4: Simplify right side
    120.98x = 18,932.17
  5. Step 5: Solve for x
    x = 18,932.17/120.98
  6. Step 6: Final answer
    x = 156.49

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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.