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Finding the Fourth Proportional to 821.31, 1,231.15 and 455.32

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Solution

The fourth proportional to 821.31, 1,231.15 and 455.32 is: 682.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.31 : 1,231.15 = 455.32 : x
  2. Step 2: Convert to fraction form
    821.31/1,231.15 = 455.32/x
  3. Step 3: Cross multiply
    821.31x = 1,231.15 × 455.32
  4. Step 4: Simplify right side
    821.31x = 560,567.22
  5. Step 5: Solve for x
    x = 560,567.22/821.31
  6. Step 6: Final answer
    x = 682.53

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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.