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Finding the Third Proportional to 1,287 and 2,686

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Solution

The third proportional to 1,287 and 2,686 is: 5,605.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287 : 2,686 = 2,686 : x
  2. Step 2: Convert to fraction form
    1,287/2,686 = 2,686/x
  3. Step 3: Cross multiply
    1,287x = 2,686 × 2,686
  4. Step 4: Simplify right side
    1,287x = 7,214,596
  5. Step 5: Solve for x
    x = 7,214,596/1,287
  6. Step 6: Final answer
    x = 5,605.75

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Why These Related Problems?

These problems maintain the same ratio (2.09) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.