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Finding the Fourth Proportional to 121.38, 180.80 and 120.66

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Solution

The fourth proportional to 121.38, 180.80 and 120.66 is: 179.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.38 : 180.80 = 120.66 : x
  2. Step 2: Convert to fraction form
    121.38/180.80 = 120.66/x
  3. Step 3: Cross multiply
    121.38x = 180.80 × 120.66
  4. Step 4: Simplify right side
    121.38x = 21,814.72
  5. Step 5: Solve for x
    x = 21,814.72/121.38
  6. Step 6: Final answer
    x = 179.72

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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.