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Finding the Fourth Proportional to 108.31, 149.40 and 66.85

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Solution

The fourth proportional to 108.31, 149.40 and 66.85 is: 92.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.31 : 149.40 = 66.85 : x
  2. Step 2: Convert to fraction form
    108.31/149.40 = 66.85/x
  3. Step 3: Cross multiply
    108.31x = 149.40 × 66.85
  4. Step 4: Simplify right side
    108.31x = 9,987.39
  5. Step 5: Solve for x
    x = 9,987.39/108.31
  6. Step 6: Final answer
    x = 92.21

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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.