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Finding the Fourth Proportional to 309.20, 426.76 and 198.68

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Solution

The fourth proportional to 309.20, 426.76 and 198.68 is: 274.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.20 : 426.76 = 198.68 : x
  2. Step 2: Convert to fraction form
    309.20/426.76 = 198.68/x
  3. Step 3: Cross multiply
    309.20x = 426.76 × 198.68
  4. Step 4: Simplify right side
    309.20x = 84,788.68
  5. Step 5: Solve for x
    x = 84,788.68/309.20
  6. Step 6: Final answer
    x = 274.22

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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.