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Finding the Fourth Proportional to 808.78, 1,213.20 and 231.70

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Solution

The fourth proportional to 808.78, 1,213.20 and 231.70 is: 347.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    808.78 : 1,213.20 = 231.70 : x
  2. Step 2: Convert to fraction form
    808.78/1,213.20 = 231.70/x
  3. Step 3: Cross multiply
    808.78x = 1,213.20 × 231.70
  4. Step 4: Simplify right side
    808.78x = 281,098.44
  5. Step 5: Solve for x
    x = 281,098.44/808.78
  6. Step 6: Final answer
    x = 347.56

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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.