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Finding the Fourth Proportional to 1,855.70, 2,781.78 and 685.43

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Solution

The fourth proportional to 1,855.70, 2,781.78 and 685.43 is: 1,027.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,855.70 : 2,781.78 = 685.43 : x
  2. Step 2: Convert to fraction form
    1,855.70/2,781.78 = 685.43/x
  3. Step 3: Cross multiply
    1,855.70x = 2,781.78 × 685.43
  4. Step 4: Simplify right side
    1,855.70x = 1,906,715.47
  5. Step 5: Solve for x
    x = 1,906,715.47/1,855.70
  6. Step 6: Final answer
    x = 1,027.49

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.