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Finding the Fourth Proportional to 87.55, 120.86 and 85.86

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Solution

The fourth proportional to 87.55, 120.86 and 85.86 is: 118.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.55 : 120.86 = 85.86 : x
  2. Step 2: Convert to fraction form
    87.55/120.86 = 85.86/x
  3. Step 3: Cross multiply
    87.55x = 120.86 × 85.86
  4. Step 4: Simplify right side
    87.55x = 10,376.93
  5. Step 5: Solve for x
    x = 10,376.93/87.55
  6. Step 6: Final answer
    x = 118.53

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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.