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Finding the Fourth Proportional to 135.62, 203.12 and 81.40

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Solution

The fourth proportional to 135.62, 203.12 and 81.40 is: 121.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    135.62 : 203.12 = 81.40 : x
  2. Step 2: Convert to fraction form
    135.62/203.12 = 81.40/x
  3. Step 3: Cross multiply
    135.62x = 203.12 × 81.40
  4. Step 4: Simplify right side
    135.62x = 16,533.97
  5. Step 5: Solve for x
    x = 16,533.97/135.62
  6. Step 6: Final answer
    x = 121.91

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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.