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Finding the Fourth Proportional to 811.56, 1,121.67 and 680.34

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Solution

The fourth proportional to 811.56, 1,121.67 and 680.34 is: 940.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.56 : 1,121.67 = 680.34 : x
  2. Step 2: Convert to fraction form
    811.56/1,121.67 = 680.34/x
  3. Step 3: Cross multiply
    811.56x = 1,121.67 × 680.34
  4. Step 4: Simplify right side
    811.56x = 763,116.97
  5. Step 5: Solve for x
    x = 763,116.97/811.56
  6. Step 6: Final answer
    x = 940.31

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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.