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Finding the Third Proportional to 678 and 1,821

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Solution

The third proportional to 678 and 1,821 is: 4,890.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    678 : 1,821 = 1,821 : x
  2. Step 2: Convert to fraction form
    678/1,821 = 1,821/x
  3. Step 3: Cross multiply
    678x = 1,821 × 1,821
  4. Step 4: Simplify right side
    678x = 3,316,041
  5. Step 5: Solve for x
    x = 3,316,041/678
  6. Step 6: Final answer
    x = 4,890.92

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Why These Related Problems?

These problems maintain the same ratio (2.69) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.