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Finding the Fourth Proportional to 812.66, 1,121.73 and 689.54

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Solution

The fourth proportional to 812.66, 1,121.73 and 689.54 is: 951.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.66 : 1,121.73 = 689.54 : x
  2. Step 2: Convert to fraction form
    812.66/1,121.73 = 689.54/x
  3. Step 3: Cross multiply
    812.66x = 1,121.73 × 689.54
  4. Step 4: Simplify right side
    812.66x = 773,477.70
  5. Step 5: Solve for x
    x = 773,477.70/812.66
  6. Step 6: Final answer
    x = 951.79

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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.