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Finding the Fourth Proportional to 108.12, 149.15 and 68.78

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Solution

The fourth proportional to 108.12, 149.15 and 68.78 is: 94.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.12 : 149.15 = 68.78 : x
  2. Step 2: Convert to fraction form
    108.12/149.15 = 68.78/x
  3. Step 3: Cross multiply
    108.12x = 149.15 × 68.78
  4. Step 4: Simplify right side
    108.12x = 10,258.54
  5. Step 5: Solve for x
    x = 10,258.54/108.12
  6. Step 6: Final answer
    x = 94.88

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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.