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Finding the Fourth Proportional to 1,371.26, 1,892.31 and 781.80

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Solution

The fourth proportional to 1,371.26, 1,892.31 and 781.80 is: 1,078.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,371.26 : 1,892.31 = 781.80 : x
  2. Step 2: Convert to fraction form
    1,371.26/1,892.31 = 781.80/x
  3. Step 3: Cross multiply
    1,371.26x = 1,892.31 × 781.80
  4. Step 4: Simplify right side
    1,371.26x = 1,479,407.96
  5. Step 5: Solve for x
    x = 1,479,407.96/1,371.26
  6. Step 6: Final answer
    x = 1,078.87

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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.