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Finding the Fourth Proportional to 821.71, 1,231.81 and 382.80

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Solution

The fourth proportional to 821.71, 1,231.81 and 382.80 is: 573.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.71 : 1,231.81 = 382.80 : x
  2. Step 2: Convert to fraction form
    821.71/1,231.81 = 382.80/x
  3. Step 3: Cross multiply
    821.71x = 1,231.81 × 382.80
  4. Step 4: Simplify right side
    821.71x = 471,536.87
  5. Step 5: Solve for x
    x = 471,536.87/821.71
  6. Step 6: Final answer
    x = 573.85

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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.