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Finding the Fourth Proportional to 140.80, 194.29 and 81.78

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Solution

The fourth proportional to 140.80, 194.29 and 81.78 is: 112.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.80 : 194.29 = 81.78 : x
  2. Step 2: Convert to fraction form
    140.80/194.29 = 81.78/x
  3. Step 3: Cross multiply
    140.80x = 194.29 × 81.78
  4. Step 4: Simplify right side
    140.80x = 15,889.04
  5. Step 5: Solve for x
    x = 15,889.04/140.80
  6. Step 6: Final answer
    x = 112.85

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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.