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Finding the Fourth Proportional to 143.62, 198.20 and 78.12

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Solution

The fourth proportional to 143.62, 198.20 and 78.12 is: 107.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.62 : 198.20 = 78.12 : x
  2. Step 2: Convert to fraction form
    143.62/198.20 = 78.12/x
  3. Step 3: Cross multiply
    143.62x = 198.20 × 78.12
  4. Step 4: Simplify right side
    143.62x = 15,483.38
  5. Step 5: Solve for x
    x = 15,483.38/143.62
  6. Step 6: Final answer
    x = 107.81

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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.