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Finding the Fourth Proportional to 108.69, 162.81 and 81.55

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Solution

The fourth proportional to 108.69, 162.81 and 81.55 is: 122.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.69 : 162.81 = 81.55 : x
  2. Step 2: Convert to fraction form
    108.69/162.81 = 81.55/x
  3. Step 3: Cross multiply
    108.69x = 162.81 × 81.55
  4. Step 4: Simplify right side
    108.69x = 13,277.16
  5. Step 5: Solve for x
    x = 13,277.16/108.69
  6. Step 6: Final answer
    x = 122.16

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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.