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Finding the Fourth Proportional to 821.21, 1,229.31 and 454.91

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Solution

The fourth proportional to 821.21, 1,229.31 and 454.91 is: 680.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.21 : 1,229.31 = 454.91 : x
  2. Step 2: Convert to fraction form
    821.21/1,229.31 = 454.91/x
  3. Step 3: Cross multiply
    821.21x = 1,229.31 × 454.91
  4. Step 4: Simplify right side
    821.21x = 559,219.27
  5. Step 5: Solve for x
    x = 559,219.27/821.21
  6. Step 6: Final answer
    x = 680.97

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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.