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Finding the Fourth Proportional to 80.65, 121.56 and 79.97

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Solution

The fourth proportional to 80.65, 121.56 and 79.97 is: 120.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.65 : 121.56 = 79.97 : x
  2. Step 2: Convert to fraction form
    80.65/121.56 = 79.97/x
  3. Step 3: Cross multiply
    80.65x = 121.56 × 79.97
  4. Step 4: Simplify right side
    80.65x = 9,720.25
  5. Step 5: Solve for x
    x = 9,720.25/80.65
  6. Step 6: Final answer
    x = 120.52

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.