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Finding the Fourth Proportional to 80.68, 121.78 and 80.68

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Solution

The fourth proportional to 80.68, 121.78 and 80.68 is: 121.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.68 : 121.78 = 80.68 : x
  2. Step 2: Convert to fraction form
    80.68/121.78 = 80.68/x
  3. Step 3: Cross multiply
    80.68x = 121.78 × 80.68
  4. Step 4: Simplify right side
    80.68x = 9,825.21
  5. Step 5: Solve for x
    x = 9,825.21/80.68
  6. Step 6: Final answer
    x = 121.78

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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.