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Finding the Fourth Proportional to 87.69, 131.01 and 85.89

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Solution

The fourth proportional to 87.69, 131.01 and 85.89 is: 128.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.69 : 131.01 = 85.89 : x
  2. Step 2: Convert to fraction form
    87.69/131.01 = 85.89/x
  3. Step 3: Cross multiply
    87.69x = 131.01 × 85.89
  4. Step 4: Simplify right side
    87.69x = 11,252.45
  5. Step 5: Solve for x
    x = 11,252.45/87.69
  6. Step 6: Final answer
    x = 128.32

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.