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Finding the Third Proportional to 390.38 and 819

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Solution

The third proportional to 390.38 and 819 is: 1,718.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.38 : 819 = 819 : x
  2. Step 2: Convert to fraction form
    390.38/819 = 819/x
  3. Step 3: Cross multiply
    390.38x = 819 × 819
  4. Step 4: Simplify right side
    390.38x = 670,761
  5. Step 5: Solve for x
    x = 670,761/390.38
  6. Step 6: Final answer
    x = 1,718.25

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Why These Related Problems?

These problems maintain the same ratio (2.10) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.