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Finding the Fourth Proportional to 85.20, 117.42 and 80.82

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Solution

The fourth proportional to 85.20, 117.42 and 80.82 is: 111.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.20 : 117.42 = 80.82 : x
  2. Step 2: Convert to fraction form
    85.20/117.42 = 80.82/x
  3. Step 3: Cross multiply
    85.20x = 117.42 × 80.82
  4. Step 4: Simplify right side
    85.20x = 9,489.88
  5. Step 5: Solve for x
    x = 9,489.88/85.20
  6. Step 6: Final answer
    x = 111.38

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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.