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Finding the Fourth Proportional to 808.74, 1,212.57 and 321.21

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Solution

The fourth proportional to 808.74, 1,212.57 and 321.21 is: 481.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    808.74 : 1,212.57 = 321.21 : x
  2. Step 2: Convert to fraction form
    808.74/1,212.57 = 321.21/x
  3. Step 3: Cross multiply
    808.74x = 1,212.57 × 321.21
  4. Step 4: Simplify right side
    808.74x = 389,489.61
  5. Step 5: Solve for x
    x = 389,489.61/808.74
  6. Step 6: Final answer
    x = 481.60

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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.