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Finding the Fourth Proportional to 121.70, 167.91 and 72.56

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Solution

The fourth proportional to 121.70, 167.91 and 72.56 is: 100.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.70 : 167.91 = 72.56 : x
  2. Step 2: Convert to fraction form
    121.70/167.91 = 72.56/x
  3. Step 3: Cross multiply
    121.70x = 167.91 × 72.56
  4. Step 4: Simplify right side
    121.70x = 12,183.55
  5. Step 5: Solve for x
    x = 12,183.55/121.70
  6. Step 6: Final answer
    x = 100.11

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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.