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Finding the Fourth Proportional to 821.44, 1,231.04 and 387.84

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Solution

The fourth proportional to 821.44, 1,231.04 and 387.84 is: 581.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.44 : 1,231.04 = 387.84 : x
  2. Step 2: Convert to fraction form
    821.44/1,231.04 = 387.84/x
  3. Step 3: Cross multiply
    821.44x = 1,231.04 × 387.84
  4. Step 4: Simplify right side
    821.44x = 477,446.55
  5. Step 5: Solve for x
    x = 477,446.55/821.44
  6. Step 6: Final answer
    x = 581.23

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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.