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Finding the Fourth Proportional to 809.20, 1,212.97 and 321.58

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Solution

The fourth proportional to 809.20, 1,212.97 and 321.58 is: 482.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.20 : 1,212.97 = 321.58 : x
  2. Step 2: Convert to fraction form
    809.20/1,212.97 = 321.58/x
  3. Step 3: Cross multiply
    809.20x = 1,212.97 × 321.58
  4. Step 4: Simplify right side
    809.20x = 390,066.89
  5. Step 5: Solve for x
    x = 390,066.89/809.20
  6. Step 6: Final answer
    x = 482.04

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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.