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Finding the Fourth Proportional to 2,206, 3,309 and 990

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Solution

The fourth proportional to 2,206, 3,309 and 990 is: 1,485

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,206 : 3,309 = 990 : x
  2. Step 2: Convert to fraction form
    2,206/3,309 = 990/x
  3. Step 3: Cross multiply
    2,206x = 3,309 × 990
  4. Step 4: Simplify right side
    2,206x = 3,275,910
  5. Step 5: Solve for x
    x = 3,275,910/2,206
  6. Step 6: Final answer
    x = 1,485

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.