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Finding the Third Proportional to 105 and 210

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Solution

The third proportional to 105 and 210 is: 420

Step by Step Solution

  1. Step 1: Write the proportion equation
    105 : 210 = 210 : x
  2. Step 2: Convert to fraction form
    105/210 = 210/x
  3. Step 3: Cross multiply
    105x = 210 × 210
  4. Step 4: Simplify right side
    105x = 44,100
  5. Step 5: Solve for x
    x = 44,100/105
  6. Step 6: Final answer
    x = 420

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Why These Related Problems?

These problems maintain the same ratio (2) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.