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Finding the Third Proportional to 396 and 870

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Solution

The third proportional to 396 and 870 is: 1,911.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    396 : 870 = 870 : x
  2. Step 2: Convert to fraction form
    396/870 = 870/x
  3. Step 3: Cross multiply
    396x = 870 × 870
  4. Step 4: Simplify right side
    396x = 756,900
  5. Step 5: Solve for x
    x = 756,900/396
  6. Step 6: Final answer
    x = 1,911.36

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These problems maintain the same ratio (2.20) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.