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Finding the Fourth Proportional to 309.45, 426.99 and 198.90

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Solution

The fourth proportional to 309.45, 426.99 and 198.90 is: 274.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.45 : 426.99 = 198.90 : x
  2. Step 2: Convert to fraction form
    309.45/426.99 = 198.90/x
  3. Step 3: Cross multiply
    309.45x = 426.99 × 198.90
  4. Step 4: Simplify right side
    309.45x = 84,927.32
  5. Step 5: Solve for x
    x = 84,927.32/309.45
  6. Step 6: Final answer
    x = 274.45

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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.