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Finding the Fourth Proportional to 809.11, 1,213.54 and 261.31

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Solution

The fourth proportional to 809.11, 1,213.54 and 261.31 is: 391.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.11 : 1,213.54 = 261.31 : x
  2. Step 2: Convert to fraction form
    809.11/1,213.54 = 261.31/x
  3. Step 3: Cross multiply
    809.11x = 1,213.54 × 261.31
  4. Step 4: Simplify right side
    809.11x = 317,110.14
  5. Step 5: Solve for x
    x = 317,110.14/809.11
  6. Step 6: Final answer
    x = 391.92

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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.