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Finding the Fourth Proportional to 87.11, 120.09 and 72.29

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Solution

The fourth proportional to 87.11, 120.09 and 72.29 is: 99.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.11 : 120.09 = 72.29 : x
  2. Step 2: Convert to fraction form
    87.11/120.09 = 72.29/x
  3. Step 3: Cross multiply
    87.11x = 120.09 × 72.29
  4. Step 4: Simplify right side
    87.11x = 8,680.71
  5. Step 5: Solve for x
    x = 8,680.71/87.11
  6. Step 6: Final answer
    x = 99.66

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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.