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Finding the Fourth Proportional to 87.89, 131.85 and 86.43

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Solution

The fourth proportional to 87.89, 131.85 and 86.43 is: 129.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.89 : 131.85 = 86.43 : x
  2. Step 2: Convert to fraction form
    87.89/131.85 = 86.43/x
  3. Step 3: Cross multiply
    87.89x = 131.85 × 86.43
  4. Step 4: Simplify right side
    87.89x = 11,395.80
  5. Step 5: Solve for x
    x = 11,395.80/87.89
  6. Step 6: Final answer
    x = 129.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.