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Finding the Fourth Proportional to 809.38, 1,213.20 and 398.36

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Solution

The fourth proportional to 809.38, 1,213.20 and 398.36 is: 597.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.38 : 1,213.20 = 398.36 : x
  2. Step 2: Convert to fraction form
    809.38/1,213.20 = 398.36/x
  3. Step 3: Cross multiply
    809.38x = 1,213.20 × 398.36
  4. Step 4: Simplify right side
    809.38x = 483,290.35
  5. Step 5: Solve for x
    x = 483,290.35/809.38
  6. Step 6: Final answer
    x = 597.11

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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.