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Finding the Fourth Proportional to 87.75, 121.23 and 81.18

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Solution

The fourth proportional to 87.75, 121.23 and 81.18 is: 112.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.75 : 121.23 = 81.18 : x
  2. Step 2: Convert to fraction form
    87.75/121.23 = 81.18/x
  3. Step 3: Cross multiply
    87.75x = 121.23 × 81.18
  4. Step 4: Simplify right side
    87.75x = 9,841.45
  5. Step 5: Solve for x
    x = 9,841.45/87.75
  6. Step 6: Final answer
    x = 112.15

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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.