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Finding the Fourth Proportional to 812.09, 1,218.50 and 427.25

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Solution

The fourth proportional to 812.09, 1,218.50 and 427.25 is: 641.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.09 : 1,218.50 = 427.25 : x
  2. Step 2: Convert to fraction form
    812.09/1,218.50 = 427.25/x
  3. Step 3: Cross multiply
    812.09x = 1,218.50 × 427.25
  4. Step 4: Simplify right side
    812.09x = 520,604.13
  5. Step 5: Solve for x
    x = 520,604.13/812.09
  6. Step 6: Final answer
    x = 641.07

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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.