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Finding the Fourth Proportional to 143.79, 198.43 and 78.30

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Solution

The fourth proportional to 143.79, 198.43 and 78.30 is: 108.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.79 : 198.43 = 78.30 : x
  2. Step 2: Convert to fraction form
    143.79/198.43 = 78.30/x
  3. Step 3: Cross multiply
    143.79x = 198.43 × 78.30
  4. Step 4: Simplify right side
    143.79x = 15,537.31
  5. Step 5: Solve for x
    x = 15,537.31/143.79
  6. Step 6: Final answer
    x = 108.05

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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.