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Finding the Fourth Proportional to 685.79, 1,028.64 and 198.86

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Solution

The fourth proportional to 685.79, 1,028.64 and 198.86 is: 298.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.79 : 1,028.64 = 198.86 : x
  2. Step 2: Convert to fraction form
    685.79/1,028.64 = 198.86/x
  3. Step 3: Cross multiply
    685.79x = 1,028.64 × 198.86
  4. Step 4: Simplify right side
    685.79x = 204,555.35
  5. Step 5: Solve for x
    x = 204,555.35/685.79
  6. Step 6: Final answer
    x = 298.28

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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.