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Finding the Fourth Proportional to 685.35, 1,028.17 and 198.40

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Solution

The fourth proportional to 685.35, 1,028.17 and 198.40 is: 297.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.35 : 1,028.17 = 198.40 : x
  2. Step 2: Convert to fraction form
    685.35/1,028.17 = 198.40/x
  3. Step 3: Cross multiply
    685.35x = 1,028.17 × 198.40
  4. Step 4: Simplify right side
    685.35x = 203,988.93
  5. Step 5: Solve for x
    x = 203,988.93/685.35
  6. Step 6: Final answer
    x = 297.64

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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.