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Finding the Third Proportional to 399 and 921

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Solution

The third proportional to 399 and 921 is: 2,125.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    399 : 921 = 921 : x
  2. Step 2: Convert to fraction form
    399/921 = 921/x
  3. Step 3: Cross multiply
    399x = 921 × 921
  4. Step 4: Simplify right side
    399x = 848,241
  5. Step 5: Solve for x
    x = 848,241/399
  6. Step 6: Final answer
    x = 2,125.92

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Why These Related Problems?

These problems maintain the same ratio (2.31) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.