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Finding the Fourth Proportional to 1,286.57, 1,776.40 and 789.89

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Solution

The fourth proportional to 1,286.57, 1,776.40 and 789.89 is: 1,090.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.57 : 1,776.40 = 789.89 : x
  2. Step 2: Convert to fraction form
    1,286.57/1,776.40 = 789.89/x
  3. Step 3: Cross multiply
    1,286.57x = 1,776.40 × 789.89
  4. Step 4: Simplify right side
    1,286.57x = 1,403,149.74
  5. Step 5: Solve for x
    x = 1,403,149.74/1,286.57
  6. Step 6: Final answer
    x = 1,090.61

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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.