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Finding the Fourth Proportional to 685.55, 1,028.21 and 198.49

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Solution

The fourth proportional to 685.55, 1,028.21 and 198.49 is: 297.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.55 : 1,028.21 = 198.49 : x
  2. Step 2: Convert to fraction form
    685.55/1,028.21 = 198.49/x
  3. Step 3: Cross multiply
    685.55x = 1,028.21 × 198.49
  4. Step 4: Simplify right side
    685.55x = 204,085.84
  5. Step 5: Solve for x
    x = 204,085.84/685.55
  6. Step 6: Final answer
    x = 297.70

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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.