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Finding the Fourth Proportional to 812.10, 1,121.73 and 681.78

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Solution

The fourth proportional to 812.10, 1,121.73 and 681.78 is: 941.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.10 : 1,121.73 = 681.78 : x
  2. Step 2: Convert to fraction form
    812.10/1,121.73 = 681.78/x
  3. Step 3: Cross multiply
    812.10x = 1,121.73 × 681.78
  4. Step 4: Simplify right side
    812.10x = 764,773.08
  5. Step 5: Solve for x
    x = 764,773.08/812.10
  6. Step 6: Final answer
    x = 941.72

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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.