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Finding the Fourth Proportional to 80.56, 111.20 and 61.20

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Solution

The fourth proportional to 80.56, 111.20 and 61.20 is: 84.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.56 : 111.20 = 61.20 : x
  2. Step 2: Convert to fraction form
    80.56/111.20 = 61.20/x
  3. Step 3: Cross multiply
    80.56x = 111.20 × 61.20
  4. Step 4: Simplify right side
    80.56x = 6,805.44
  5. Step 5: Solve for x
    x = 6,805.44/80.56
  6. Step 6: Final answer
    x = 84.48

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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.