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Finding the Third Proportional to 220 and 399

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Solution

The third proportional to 220 and 399 is: 723.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    220 : 399 = 399 : x
  2. Step 2: Convert to fraction form
    220/399 = 399/x
  3. Step 3: Cross multiply
    220x = 399 × 399
  4. Step 4: Simplify right side
    220x = 159,201
  5. Step 5: Solve for x
    x = 159,201/220
  6. Step 6: Final answer
    x = 723.64

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Why These Related Problems?

These problems maintain the same ratio (1.81) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.