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Finding the Fourth Proportional to 809.21, 1,213.82 and 261.43

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Solution

The fourth proportional to 809.21, 1,213.82 and 261.43 is: 392.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.21 : 1,213.82 = 261.43 : x
  2. Step 2: Convert to fraction form
    809.21/1,213.82 = 261.43/x
  3. Step 3: Cross multiply
    809.21x = 1,213.82 × 261.43
  4. Step 4: Simplify right side
    809.21x = 317,326.58
  5. Step 5: Solve for x
    x = 317,326.58/809.21
  6. Step 6: Final answer
    x = 392.14

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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.