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Finding the Fourth Proportional to 812.90, 1,121.99 and 679.97

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Solution

The fourth proportional to 812.90, 1,121.99 and 679.97 is: 938.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.90 : 1,121.99 = 679.97 : x
  2. Step 2: Convert to fraction form
    812.90/1,121.99 = 679.97/x
  3. Step 3: Cross multiply
    812.90x = 1,121.99 × 679.97
  4. Step 4: Simplify right side
    812.90x = 762,918.95
  5. Step 5: Solve for x
    x = 762,918.95/812.90
  6. Step 6: Final answer
    x = 938.51

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.