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Finding the Fourth Proportional to 108.40, 149.32 and 85

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Solution

The fourth proportional to 108.40, 149.32 and 85 is: 117.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.40 : 149.32 = 85 : x
  2. Step 2: Convert to fraction form
    108.40/149.32 = 85/x
  3. Step 3: Cross multiply
    108.40x = 149.32 × 85
  4. Step 4: Simplify right side
    108.40x = 12,692.20
  5. Step 5: Solve for x
    x = 12,692.20/108.40
  6. Step 6: Final answer
    x = 117.09

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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.