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Finding the Fourth Proportional to 121.45, 167.55 and 72.31

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Solution

The fourth proportional to 121.45, 167.55 and 72.31 is: 99.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.45 : 167.55 = 72.31 : x
  2. Step 2: Convert to fraction form
    121.45/167.55 = 72.31/x
  3. Step 3: Cross multiply
    121.45x = 167.55 × 72.31
  4. Step 4: Simplify right side
    121.45x = 12,115.54
  5. Step 5: Solve for x
    x = 12,115.54/121.45
  6. Step 6: Final answer
    x = 99.76

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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.