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Finding the Fourth Proportional to 811.10, 1,215.84 and 323.90

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Solution

The fourth proportional to 811.10, 1,215.84 and 323.90 is: 485.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.10 : 1,215.84 = 323.90 : x
  2. Step 2: Convert to fraction form
    811.10/1,215.84 = 323.90/x
  3. Step 3: Cross multiply
    811.10x = 1,215.84 × 323.90
  4. Step 4: Simplify right side
    811.10x = 393,810.58
  5. Step 5: Solve for x
    x = 393,810.58/811.10
  6. Step 6: Final answer
    x = 485.53

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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.