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Finding the Fourth Proportional to 143.78, 198.42 and 78.28

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Solution

The fourth proportional to 143.78, 198.42 and 78.28 is: 108.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.78 : 198.42 = 78.28 : x
  2. Step 2: Convert to fraction form
    143.78/198.42 = 78.28/x
  3. Step 3: Cross multiply
    143.78x = 198.42 × 78.28
  4. Step 4: Simplify right side
    143.78x = 15,531.93
  5. Step 5: Solve for x
    x = 15,531.93/143.78
  6. Step 6: Final answer
    x = 108.03

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.