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Finding the Third Proportional to 687 and 1,368

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Solution

The third proportional to 687 and 1,368 is: 2,724.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    687 : 1,368 = 1,368 : x
  2. Step 2: Convert to fraction form
    687/1,368 = 1,368/x
  3. Step 3: Cross multiply
    687x = 1,368 × 1,368
  4. Step 4: Simplify right side
    687x = 1,871,424
  5. Step 5: Solve for x
    x = 1,871,424/687
  6. Step 6: Final answer
    x = 2,724.05

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Why These Related Problems?

These problems maintain the same ratio (1.99) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.