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Finding the Fourth Proportional to 87.42, 120.39 and 79.26

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Solution

The fourth proportional to 87.42, 120.39 and 79.26 is: 109.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.42 : 120.39 = 79.26 : x
  2. Step 2: Convert to fraction form
    87.42/120.39 = 79.26/x
  3. Step 3: Cross multiply
    87.42x = 120.39 × 79.26
  4. Step 4: Simplify right side
    87.42x = 9,542.11
  5. Step 5: Solve for x
    x = 9,542.11/87.42
  6. Step 6: Final answer
    x = 109.15

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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.