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Finding the Fourth Proportional to 685.20, 1,027.99 and 198.30

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Solution

The fourth proportional to 685.20, 1,027.99 and 198.30 is: 297.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.20 : 1,027.99 = 198.30 : x
  2. Step 2: Convert to fraction form
    685.20/1,027.99 = 198.30/x
  3. Step 3: Cross multiply
    685.20x = 1,027.99 × 198.30
  4. Step 4: Simplify right side
    685.20x = 203,850.42
  5. Step 5: Solve for x
    x = 203,850.42/685.20
  6. Step 6: Final answer
    x = 297.50

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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.