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Finding the Fourth Proportional to 80.96, 121.28 and 71.20

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Solution

The fourth proportional to 80.96, 121.28 and 71.20 is: 106.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.96 : 121.28 = 71.20 : x
  2. Step 2: Convert to fraction form
    80.96/121.28 = 71.20/x
  3. Step 3: Cross multiply
    80.96x = 121.28 × 71.20
  4. Step 4: Simplify right side
    80.96x = 8,635.14
  5. Step 5: Solve for x
    x = 8,635.14/80.96
  6. Step 6: Final answer
    x = 106.66

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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.