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Finding the Fourth Proportional to 811, 1,215.85 and 323.92

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Solution

The fourth proportional to 811, 1,215.85 and 323.92 is: 485.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    811 : 1,215.85 = 323.92 : x
  2. Step 2: Convert to fraction form
    811/1,215.85 = 323.92/x
  3. Step 3: Cross multiply
    811x = 1,215.85 × 323.92
  4. Step 4: Simplify right side
    811x = 393,838.13
  5. Step 5: Solve for x
    x = 393,838.13/811
  6. Step 6: Final answer
    x = 485.62

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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.