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Finding the Fourth Proportional to 108.21, 161.71 and 80.85

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Solution

The fourth proportional to 108.21, 161.71 and 80.85 is: 120.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.21 : 161.71 = 80.85 : x
  2. Step 2: Convert to fraction form
    108.21/161.71 = 80.85/x
  3. Step 3: Cross multiply
    108.21x = 161.71 × 80.85
  4. Step 4: Simplify right side
    108.21x = 13,074.25
  5. Step 5: Solve for x
    x = 13,074.25/108.21
  6. Step 6: Final answer
    x = 120.82

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.