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Finding the Fourth Proportional to 121.55, 167.76 and 72.42

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Solution

The fourth proportional to 121.55, 167.76 and 72.42 is: 99.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.55 : 167.76 = 72.42 : x
  2. Step 2: Convert to fraction form
    121.55/167.76 = 72.42/x
  3. Step 3: Cross multiply
    121.55x = 167.76 × 72.42
  4. Step 4: Simplify right side
    121.55x = 12,147.98
  5. Step 5: Solve for x
    x = 12,147.98/121.55
  6. Step 6: Final answer
    x = 99.95

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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.