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Finding the Fourth Proportional to 154.56, 213.12 and 121.80

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Solution

The fourth proportional to 154.56, 213.12 and 121.80 is: 167.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.56 : 213.12 = 121.80 : x
  2. Step 2: Convert to fraction form
    154.56/213.12 = 121.80/x
  3. Step 3: Cross multiply
    154.56x = 213.12 × 121.80
  4. Step 4: Simplify right side
    154.56x = 25,958.02
  5. Step 5: Solve for x
    x = 25,958.02/154.56
  6. Step 6: Final answer
    x = 167.95

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.