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Finding the Fourth Proportional to 135.21, 202.86 and 81.15

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Solution

The fourth proportional to 135.21, 202.86 and 81.15 is: 121.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    135.21 : 202.86 = 81.15 : x
  2. Step 2: Convert to fraction form
    135.21/202.86 = 81.15/x
  3. Step 3: Cross multiply
    135.21x = 202.86 × 81.15
  4. Step 4: Simplify right side
    135.21x = 16,462.09
  5. Step 5: Solve for x
    x = 16,462.09/135.21
  6. Step 6: Final answer
    x = 121.75

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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.