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Finding the Third Proportional to 390.38 and 861.75

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Solution

The third proportional to 390.38 and 861.75 is: 1,902.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.38 : 861.75 = 861.75 : x
  2. Step 2: Convert to fraction form
    390.38/861.75 = 861.75/x
  3. Step 3: Cross multiply
    390.38x = 861.75 × 861.75
  4. Step 4: Simplify right side
    390.38x = 742,613.06
  5. Step 5: Solve for x
    x = 742,613.06/390.38
  6. Step 6: Final answer
    x = 1,902.31

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Why These Related Problems?

These problems maintain the same ratio (2.21) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.