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Finding the Fourth Proportional to 809.88, 1,115.70 and 685.14

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Solution

The fourth proportional to 809.88, 1,115.70 and 685.14 is: 943.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.88 : 1,115.70 = 685.14 : x
  2. Step 2: Convert to fraction form
    809.88/1,115.70 = 685.14/x
  3. Step 3: Cross multiply
    809.88x = 1,115.70 × 685.14
  4. Step 4: Simplify right side
    809.88x = 764,410.70
  5. Step 5: Solve for x
    x = 764,410.70/809.88
  6. Step 6: Final answer
    x = 943.86

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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.