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Finding the Fourth Proportional to 808.31, 1,213.07 and 321.40

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Solution

The fourth proportional to 808.31, 1,213.07 and 321.40 is: 482.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    808.31 : 1,213.07 = 321.40 : x
  2. Step 2: Convert to fraction form
    808.31/1,213.07 = 321.40/x
  3. Step 3: Cross multiply
    808.31x = 1,213.07 × 321.40
  4. Step 4: Simplify right side
    808.31x = 389,880.70
  5. Step 5: Solve for x
    x = 389,880.70/808.31
  6. Step 6: Final answer
    x = 482.34

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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.