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Finding the Fourth Proportional to 80.80, 111.34 and 78.43

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Solution

The fourth proportional to 80.80, 111.34 and 78.43 is: 108.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.80 : 111.34 = 78.43 : x
  2. Step 2: Convert to fraction form
    80.80/111.34 = 78.43/x
  3. Step 3: Cross multiply
    80.80x = 111.34 × 78.43
  4. Step 4: Simplify right side
    80.80x = 8,732.40
  5. Step 5: Solve for x
    x = 8,732.40/80.80
  6. Step 6: Final answer
    x = 108.07

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.