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Finding the Fourth Proportional to 811.20, 1,215.96 and 323.56

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Solution

The fourth proportional to 811.20, 1,215.96 and 323.56 is: 485.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.20 : 1,215.96 = 323.56 : x
  2. Step 2: Convert to fraction form
    811.20/1,215.96 = 323.56/x
  3. Step 3: Cross multiply
    811.20x = 1,215.96 × 323.56
  4. Step 4: Simplify right side
    811.20x = 393,436.02
  5. Step 5: Solve for x
    x = 393,436.02/811.20
  6. Step 6: Final answer
    x = 485.00

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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.