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Finding the Third Proportional to 405 and 855

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Solution

The third proportional to 405 and 855 is: 1,805

Step by Step Solution

  1. Step 1: Write the proportion equation
    405 : 855 = 855 : x
  2. Step 2: Convert to fraction form
    405/855 = 855/x
  3. Step 3: Cross multiply
    405x = 855 × 855
  4. Step 4: Simplify right side
    405x = 731,025
  5. Step 5: Solve for x
    x = 731,025/405
  6. Step 6: Final answer
    x = 1,805

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Why These Related Problems?

These problems maintain the same ratio (2.11) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.