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Finding the Fourth Proportional to 84.87, 127.31 and 80.43

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Solution

The fourth proportional to 84.87, 127.31 and 80.43 is: 120.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.87 : 127.31 = 80.43 : x
  2. Step 2: Convert to fraction form
    84.87/127.31 = 80.43/x
  3. Step 3: Cross multiply
    84.87x = 127.31 × 80.43
  4. Step 4: Simplify right side
    84.87x = 10,238.89
  5. Step 5: Solve for x
    x = 10,238.89/84.87
  6. Step 6: Final answer
    x = 120.64

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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.