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Finding the Fourth Proportional to 86.69, 120.43 and 85.86

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Solution

The fourth proportional to 86.69, 120.43 and 85.86 is: 119.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.69 : 120.43 = 85.86 : x
  2. Step 2: Convert to fraction form
    86.69/120.43 = 85.86/x
  3. Step 3: Cross multiply
    86.69x = 120.43 × 85.86
  4. Step 4: Simplify right side
    86.69x = 10,339.91
  5. Step 5: Solve for x
    x = 10,339.91/86.69
  6. Step 6: Final answer
    x = 119.27

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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.