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Finding the Fourth Proportional to 820.43, 1,231.27 and 387.89

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Solution

The fourth proportional to 820.43, 1,231.27 and 387.89 is: 582.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.43 : 1,231.27 = 387.89 : x
  2. Step 2: Convert to fraction form
    820.43/1,231.27 = 387.89/x
  3. Step 3: Cross multiply
    820.43x = 1,231.27 × 387.89
  4. Step 4: Simplify right side
    820.43x = 477,594.81
  5. Step 5: Solve for x
    x = 477,594.81/820.43
  6. Step 6: Final answer
    x = 582.13

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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.