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Finding the Fourth Proportional to 87.09, 120.13 and 61.21

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Solution

The fourth proportional to 87.09, 120.13 and 61.21 is: 84.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.09 : 120.13 = 61.21 : x
  2. Step 2: Convert to fraction form
    87.09/120.13 = 61.21/x
  3. Step 3: Cross multiply
    87.09x = 120.13 × 61.21
  4. Step 4: Simplify right side
    87.09x = 7,353.16
  5. Step 5: Solve for x
    x = 7,353.16/87.09
  6. Step 6: Final answer
    x = 84.43

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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.