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Finding the Fourth Proportional to 80.56, 111 and 72.78

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Solution

The fourth proportional to 80.56, 111 and 72.78 is: 100.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.56 : 111 = 72.78 : x
  2. Step 2: Convert to fraction form
    80.56/111 = 72.78/x
  3. Step 3: Cross multiply
    80.56x = 111 × 72.78
  4. Step 4: Simplify right side
    80.56x = 8,078.58
  5. Step 5: Solve for x
    x = 8,078.58/80.56
  6. Step 6: Final answer
    x = 100.28

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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.