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Finding the Fourth Proportional to 1,371.28, 1,892.46 and 781.70

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Solution

The fourth proportional to 1,371.28, 1,892.46 and 781.70 is: 1,078.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,371.28 : 1,892.46 = 781.70 : x
  2. Step 2: Convert to fraction form
    1,371.28/1,892.46 = 781.70/x
  3. Step 3: Cross multiply
    1,371.28x = 1,892.46 × 781.70
  4. Step 4: Simplify right side
    1,371.28x = 1,479,335.98
  5. Step 5: Solve for x
    x = 1,479,335.98/1,371.28
  6. Step 6: Final answer
    x = 1,078.80

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1.5x scale

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.