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Finding the Fourth Proportional to 84.42, 115.87 and 80.90

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Solution

The fourth proportional to 84.42, 115.87 and 80.90 is: 111.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.42 : 115.87 = 80.90 : x
  2. Step 2: Convert to fraction form
    84.42/115.87 = 80.90/x
  3. Step 3: Cross multiply
    84.42x = 115.87 × 80.90
  4. Step 4: Simplify right side
    84.42x = 9,373.88
  5. Step 5: Solve for x
    x = 9,373.88/84.42
  6. Step 6: Final answer
    x = 111.04

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.