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Finding the Fourth Proportional to 80.68, 121.20 and 79.60

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Solution

The fourth proportional to 80.68, 121.20 and 79.60 is: 119.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.68 : 121.20 = 79.60 : x
  2. Step 2: Convert to fraction form
    80.68/121.20 = 79.60/x
  3. Step 3: Cross multiply
    80.68x = 121.20 × 79.60
  4. Step 4: Simplify right side
    80.68x = 9,647.52
  5. Step 5: Solve for x
    x = 9,647.52/80.68
  6. Step 6: Final answer
    x = 119.58

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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.