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Finding the Fourth Proportional to 135.72, 203.22 and 81.36

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Solution

The fourth proportional to 135.72, 203.22 and 81.36 is: 121.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    135.72 : 203.22 = 81.36 : x
  2. Step 2: Convert to fraction form
    135.72/203.22 = 81.36/x
  3. Step 3: Cross multiply
    135.72x = 203.22 × 81.36
  4. Step 4: Simplify right side
    135.72x = 16,533.98
  5. Step 5: Solve for x
    x = 16,533.98/135.72
  6. Step 6: Final answer
    x = 121.82

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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.