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Finding the Fourth Proportional to 87.58, 121.36 and 84.39

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Solution

The fourth proportional to 87.58, 121.36 and 84.39 is: 116.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.58 : 121.36 = 84.39 : x
  2. Step 2: Convert to fraction form
    87.58/121.36 = 84.39/x
  3. Step 3: Cross multiply
    87.58x = 121.36 × 84.39
  4. Step 4: Simplify right side
    87.58x = 10,241.57
  5. Step 5: Solve for x
    x = 10,241.57/87.58
  6. Step 6: Final answer
    x = 116.94

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.