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Finding the Fourth Proportional to 86.83, 120.32 and 83.64

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Solution

The fourth proportional to 86.83, 120.32 and 83.64 is: 115.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.83 : 120.32 = 83.64 : x
  2. Step 2: Convert to fraction form
    86.83/120.32 = 83.64/x
  3. Step 3: Cross multiply
    86.83x = 120.32 × 83.64
  4. Step 4: Simplify right side
    86.83x = 10,063.56
  5. Step 5: Solve for x
    x = 10,063.56/86.83
  6. Step 6: Final answer
    x = 115.90

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.