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Finding the Fourth Proportional to 87.16, 120.17 and 72.42

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Solution

The fourth proportional to 87.16, 120.17 and 72.42 is: 99.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.16 : 120.17 = 72.42 : x
  2. Step 2: Convert to fraction form
    87.16/120.17 = 72.42/x
  3. Step 3: Cross multiply
    87.16x = 120.17 × 72.42
  4. Step 4: Simplify right side
    87.16x = 8,702.53
  5. Step 5: Solve for x
    x = 8,702.53/87.16
  6. Step 6: Final answer
    x = 99.85

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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.