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Finding the Fourth Proportional to 812.36, 1,121.83 and 647.79

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Solution

The fourth proportional to 812.36, 1,121.83 and 647.79 is: 894.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.36 : 1,121.83 = 647.79 : x
  2. Step 2: Convert to fraction form
    812.36/1,121.83 = 647.79/x
  3. Step 3: Cross multiply
    812.36x = 1,121.83 × 647.79
  4. Step 4: Simplify right side
    812.36x = 726,704.43
  5. Step 5: Solve for x
    x = 726,704.43/812.36
  6. Step 6: Final answer
    x = 894.56

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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.