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Finding the Fourth Proportional to 168.78, 253.09 and 87.61

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Solution

The fourth proportional to 168.78, 253.09 and 87.61 is: 131.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    168.78 : 253.09 = 87.61 : x
  2. Step 2: Convert to fraction form
    168.78/253.09 = 87.61/x
  3. Step 3: Cross multiply
    168.78x = 253.09 × 87.61
  4. Step 4: Simplify right side
    168.78x = 22,173.21
  5. Step 5: Solve for x
    x = 22,173.21/168.78
  6. Step 6: Final answer
    x = 131.37

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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.