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Finding the Fourth Proportional to 87.35, 131.69 and 81.47

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Solution

The fourth proportional to 87.35, 131.69 and 81.47 is: 122.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.35 : 131.69 = 81.47 : x
  2. Step 2: Convert to fraction form
    87.35/131.69 = 81.47/x
  3. Step 3: Cross multiply
    87.35x = 131.69 × 81.47
  4. Step 4: Simplify right side
    87.35x = 10,729.32
  5. Step 5: Solve for x
    x = 10,729.32/87.35
  6. Step 6: Final answer
    x = 122.84

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.