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Finding the Fourth Proportional to 135.78, 203.51 and 81.71

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Solution

The fourth proportional to 135.78, 203.51 and 81.71 is: 122.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    135.78 : 203.51 = 81.71 : x
  2. Step 2: Convert to fraction form
    135.78/203.51 = 81.71/x
  3. Step 3: Cross multiply
    135.78x = 203.51 × 81.71
  4. Step 4: Simplify right side
    135.78x = 16,628.75
  5. Step 5: Solve for x
    x = 16,628.75/135.78
  6. Step 6: Final answer
    x = 122.47

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.