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Finding the Fourth Proportional to 821.18, 1,230.81 and 455.42

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Solution

The fourth proportional to 821.18, 1,230.81 and 455.42 is: 682.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.18 : 1,230.81 = 455.42 : x
  2. Step 2: Convert to fraction form
    821.18/1,230.81 = 455.42/x
  3. Step 3: Cross multiply
    821.18x = 1,230.81 × 455.42
  4. Step 4: Simplify right side
    821.18x = 560,535.49
  5. Step 5: Solve for x
    x = 560,535.49/821.18
  6. Step 6: Final answer
    x = 682.60

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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.