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Finding the Third Proportional to 289.69 and 687.09

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Solution

The third proportional to 289.69 and 687.09 is: 1,629.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.69 : 687.09 = 687.09 : x
  2. Step 2: Convert to fraction form
    289.69/687.09 = 687.09/x
  3. Step 3: Cross multiply
    289.69x = 687.09 × 687.09
  4. Step 4: Simplify right side
    289.69x = 472,097.82
  5. Step 5: Solve for x
    x = 472,097.82/289.69
  6. Step 6: Final answer
    x = 1,629.68

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Why These Related Problems?

These problems maintain the same ratio (2.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.