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Finding the Third Proportional to 399 and 485

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Solution

The third proportional to 399 and 485 is: 589.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    399 : 485 = 485 : x
  2. Step 2: Convert to fraction form
    399/485 = 485/x
  3. Step 3: Cross multiply
    399x = 485 × 485
  4. Step 4: Simplify right side
    399x = 235,225
  5. Step 5: Solve for x
    x = 235,225/399
  6. Step 6: Final answer
    x = 589.54

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Why These Related Problems?

These problems maintain the same ratio (1.22) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.