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Finding the Fourth Proportional to 811.98, 1,218.42 and 324.90

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Solution

The fourth proportional to 811.98, 1,218.42 and 324.90 is: 487.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.98 : 1,218.42 = 324.90 : x
  2. Step 2: Convert to fraction form
    811.98/1,218.42 = 324.90/x
  3. Step 3: Cross multiply
    811.98x = 1,218.42 × 324.90
  4. Step 4: Simplify right side
    811.98x = 395,864.66
  5. Step 5: Solve for x
    x = 395,864.66/811.98
  6. Step 6: Final answer
    x = 487.53

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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.