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Finding the Fourth Proportional to 80.89, 121.28 and 72.79

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Solution

The fourth proportional to 80.89, 121.28 and 72.79 is: 109.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.89 : 121.28 = 72.79 : x
  2. Step 2: Convert to fraction form
    80.89/121.28 = 72.79/x
  3. Step 3: Cross multiply
    80.89x = 121.28 × 72.79
  4. Step 4: Simplify right side
    80.89x = 8,827.97
  5. Step 5: Solve for x
    x = 8,827.97/80.89
  6. Step 6: Final answer
    x = 109.14

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.