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Finding the Fourth Proportional to 109.16, 163.91 and 81.82

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Solution

The fourth proportional to 109.16, 163.91 and 81.82 is: 122.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.16 : 163.91 = 81.82 : x
  2. Step 2: Convert to fraction form
    109.16/163.91 = 81.82/x
  3. Step 3: Cross multiply
    109.16x = 163.91 × 81.82
  4. Step 4: Simplify right side
    109.16x = 13,411.12
  5. Step 5: Solve for x
    x = 13,411.12/109.16
  6. Step 6: Final answer
    x = 122.86

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.