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Finding the Fourth Proportional to 168.78, 253.29 and 128.22

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Solution

The fourth proportional to 168.78, 253.29 and 128.22 is: 192.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    168.78 : 253.29 = 128.22 : x
  2. Step 2: Convert to fraction form
    168.78/253.29 = 128.22/x
  3. Step 3: Cross multiply
    168.78x = 253.29 × 128.22
  4. Step 4: Simplify right side
    168.78x = 32,476.84
  5. Step 5: Solve for x
    x = 32,476.84/168.78
  6. Step 6: Final answer
    x = 192.42

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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.