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Finding the Fourth Proportional to 121.80, 169.19 and 118.38

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Solution

The fourth proportional to 121.80, 169.19 and 118.38 is: 164.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.80 : 169.19 = 118.38 : x
  2. Step 2: Convert to fraction form
    121.80/169.19 = 118.38/x
  3. Step 3: Cross multiply
    121.80x = 169.19 × 118.38
  4. Step 4: Simplify right side
    121.80x = 20,028.12
  5. Step 5: Solve for x
    x = 20,028.12/121.80
  6. Step 6: Final answer
    x = 164.43

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.