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Finding the Fourth Proportional to 1,286.68, 1,774.97 and 813.78

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Solution

The fourth proportional to 1,286.68, 1,774.97 and 813.78 is: 1,122.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.68 : 1,774.97 = 813.78 : x
  2. Step 2: Convert to fraction form
    1,286.68/1,774.97 = 813.78/x
  3. Step 3: Cross multiply
    1,286.68x = 1,774.97 × 813.78
  4. Step 4: Simplify right side
    1,286.68x = 1,444,422.14
  5. Step 5: Solve for x
    x = 1,444,422.14/1,286.68
  6. Step 6: Final answer
    x = 1,122.60

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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.