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Finding the Fourth Proportional to 108.20, 161.96 and 77.28

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Solution

The fourth proportional to 108.20, 161.96 and 77.28 is: 115.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.20 : 161.96 = 77.28 : x
  2. Step 2: Convert to fraction form
    108.20/161.96 = 77.28/x
  3. Step 3: Cross multiply
    108.20x = 161.96 × 77.28
  4. Step 4: Simplify right side
    108.20x = 12,516.27
  5. Step 5: Solve for x
    x = 12,516.27/108.20
  6. Step 6: Final answer
    x = 115.68

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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.