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Finding the Fourth Proportional to 812.57, 1,218.34 and 343.80

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Solution

The fourth proportional to 812.57, 1,218.34 and 343.80 is: 515.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.57 : 1,218.34 = 343.80 : x
  2. Step 2: Convert to fraction form
    812.57/1,218.34 = 343.80/x
  3. Step 3: Cross multiply
    812.57x = 1,218.34 × 343.80
  4. Step 4: Simplify right side
    812.57x = 418,866.69
  5. Step 5: Solve for x
    x = 418,866.69/812.57
  6. Step 6: Final answer
    x = 515.48

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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.