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Finding the Fourth Proportional to 812.42, 1,218.82 and 447.12

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Solution

The fourth proportional to 812.42, 1,218.82 and 447.12 is: 670.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.42 : 1,218.82 = 447.12 : x
  2. Step 2: Convert to fraction form
    812.42/1,218.82 = 447.12/x
  3. Step 3: Cross multiply
    812.42x = 1,218.82 × 447.12
  4. Step 4: Simplify right side
    812.42x = 544,958.80
  5. Step 5: Solve for x
    x = 544,958.80/812.42
  6. Step 6: Final answer
    x = 670.78

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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.